diff --git a/Zadanie-4/poly.py b/Zadanie-4/poly.py
new file mode 100644
index 0000000..ab3ac44
--- /dev/null
+++ b/Zadanie-4/poly.py
@@ -0,0 +1,83 @@
+import sys
+import ast
+
+class Polynomial:
+    
+    n = 0
+
+    def __init__(self, coeff_list):
+        self.degree = len(coeff_list) - 1
+        self.coefficients = [x % Polynomial.n for x in coeff_list]
+
+    def __pow__(self, n):
+        result = self
+        for i in range(n):
+            result = Polynomial.multiply(result, result)
+        return result
+
+    @staticmethod
+    def add(p1, p2):
+        result = []
+        f = p1.coefficients
+        g = p2.coefficients
+        if len(f) >= len(g):
+            result = f
+            for i in range(len(g)):
+                result[i] = f[i] + g[i]
+        else:
+            result = g
+            for i in range(len(f)):
+                result[i] = f[i] + g[i]
+        result = [x % int(Polynomial.n) for x in result]        
+        return Polynomial(result)
+
+    @staticmethod
+    def multiply(p1, p2):
+        result = [0] * (p1.degree + p2.degree + 1)
+        f = p1.coefficients
+        g = p2.coefficients
+        for i in range(len(f)):
+            for j in range(len(g)):
+                result[i+j] += f[i] * g[j]
+        result = [x % int(Polynomial.n) for x in result]
+        return Polynomial(result)
+
+    @staticmethod
+    def divide(p1, p2):          
+        
+        def inverse(x):
+            for i in range(1, int(Polynomial.n)):
+                r = (i * x) % int(Polynomial.n)
+                if r == 1:
+                    break
+            else:
+                raise ZeroDivisionError
+            return i    
+           
+        if p1.degree < p2.degree:
+            return p1
+        f = p1.coefficients
+        g = p2.coefficients
+        g_lead_coef = g[-1]
+        g_deg = p2.degree
+        while len(f) >= len(g):
+            f_lead_coef = f[-1]
+            tmp_coef = f_lead_coef * inverse(g_lead_coef)
+            tmp_exp = len(f) - 1 - g_deg
+            tmp = []
+            for _ in range(tmp_exp):
+                tmp.append(0)
+            tmp.append(tmp_coef)
+            tmp_poly = Polynomial(tmp)
+            sub = Polynomial.multiply(p2, tmp_poly)
+            f = [x - y for x, y in zip(f, sub.coefficients)]
+            f = [x % int(Polynomial.n) for x in f]
+            while f and f[-1] == 0:
+                f.pop()
+        return Polynomial(f)
+
+    @staticmethod
+    def gcd(p1, p2):
+        if len(p2.coefficients) == 0:
+            return p1
+        return Polynomial.gcd(p2, Polynomial.divide(p1, p2))
diff --git a/Zadanie-4/quotient_ring.py b/Zadanie-4/quotient_ring.py
new file mode 100644
index 0000000..f9e963b
--- /dev/null
+++ b/Zadanie-4/quotient_ring.py
@@ -0,0 +1,88 @@
+from poly import Polynomial as P
+import sys
+import ast
+
+class QuotientRing:
+
+    def __init__(self, coeffs):
+        self.fx = P(coeffs)
+        self.remainder_set = self.create_remainder_set()
+        self.invertible_elements = self.get_invertible_elements()
+        self.zero_divisors = self.get_zero_divisors()
+        self.nilpotent_elements = self.get_nilpotent_elements()
+        self.idempotent_elements = self.get_idempotent_elements()
+
+    def create_remainder_set(self):
+        remainders = []
+        rem = [0]
+        i = 0
+        while len(rem) < len(self.fx.coefficients):
+            remainders.append(P(rem))
+            i = (i + 1) % P.n
+            rem[0] = i
+            if i == 0:
+                if len(rem) == 1:
+                    rem.append(1)
+                else:
+                    rem[1] += 1
+                    for j in range(1, len(rem)):
+                        if rem[j] == 0 or rem[j] % P.n != 0:
+                            break
+                        tmp = rem[j] % P.n
+                        rem[j] = 0
+                        if tmp == 0:
+                            if (j + 1) < len(rem):
+                                rem[j+1] += 1
+                            else:
+                                rem.append(1)
+        return remainders
+
+    def get_invertible_elements(self):
+        invertible_elements = []
+        for i in self.remainder_set:
+            if i.coefficients != [0] and len(P.gcd(self.fx, i).coefficients) == 1:
+                invertible_elements.append(i)
+        return invertible_elements
+
+    def get_zero_divisors(self):
+        zero_diviors = []
+        for i in self.remainder_set:
+            if i not in self.invertible_elements:
+                zero_diviors.append(i)
+        return zero_diviors
+
+    def get_nilpotent_elements(self):
+        nilpotent_elements = []
+        for i in self.zero_divisors:
+            for j in range(1, len(self.invertible_elements) + 1):
+                if i.coefficients == [0] or len(P.divide(i**j, self.fx).coefficients) == 0:
+                    nilpotent_elements.append(i)
+                break
+        return nilpotent_elements
+
+    def get_idempotent_elements(self):
+        idempotent_elements = []
+        for i in self.remainder_set:
+            if P.divide(i**2, self.fx).coefficients == P.divide(i, self.fx).coefficients:
+                idempotent_elements.append(i)
+        return idempotent_elements
+
+
+def main():
+    P.n = int(sys.argv[1])
+    coeffs = ast.literal_eval(sys.argv[2])
+    Q = QuotientRing(coeffs)
+    
+    ans = [
+            [x.coefficients for x in Q.invertible_elements],
+            [x.coefficients for x in Q.zero_divisors],
+            [x.coefficients for x in Q.nilpotent_elements],
+            [x.coefficients for x in Q.idempotent_elements]
+          ] 
+    
+    for i in range(len(ans)):
+        print(ans[i])
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file