diff --git a/TaskB09/fsa_description.arg b/TaskB09/fsa_description.arg
new file mode 100644
index 0000000..6950f75
--- /dev/null
+++ b/TaskB09/fsa_description.arg
@@ -0,0 +1,22 @@
+0	1	m
+1	2	a
+2	3	c
+3	4	b
+4	5	e
+5	6	t
+6	7	h
+1	1	m
+2	1	m
+3	1	m
+4	1	m
+5	1	m
+6	1	m
+7	7	abcdefghijklmnopqrstuvwxyz 
+0	0	abcdefghijklnopqrstuvwxyz 
+1	0	bcdefghijklnopqrstuvwxyz 
+2	0	abdefghijklnopqrstuvwxyz 
+3	0	acdefghijklnopqrstuvwxyz 
+4	0	abcdfghijklnopqrstuvwxyz 
+5	0	abcdefghijklnopqrsuvwxyz 
+6	0	abcdefgijklnopqrstuvwxyz 
+7
\ No newline at end of file
diff --git a/TaskB09/run.py b/TaskB09/run.py
new file mode 100644
index 0000000..871f28c
--- /dev/null
+++ b/TaskB09/run.py
@@ -0,0 +1,101 @@
+import sys
+import csv
+import os
+
+from numpy import append
+
+DIR = os.path.dirname(__file__)
+alfabet = "abcdefghijklmnopqrstuvwxyz "
+
+
+def join_path(filename: str) -> str:
+    return os.path.join(DIR, filename)
+
+
+if len(sys.argv) == 1:
+    print("Default arguments parsed\n")
+    sys.argv.append("fsa_description.arg")
+    sys.argv.append("simple.in")
+    sys.argv.append("simple.exp")
+
+with open(join_path(sys.argv[1]), "r", newline="", encoding="utf8") as csvfile:
+    filereader = csv.reader(csvfile, delimiter="\t", quotechar="|")
+    fsa_description = list(filereader)
+    accepting_state = int(fsa_description[-1][0])
+    fsa_description = fsa_description[:-1]
+    fsa_description_map = {}
+    is_error = False
+    for num, item in enumerate(fsa_description):
+        for letter in item[2]:
+            if letter not in alfabet:
+                print("ERROR - letter not in alfabet: ", letter, "| line:", num + 1)
+                exit(-1)
+            if (int(item[0]), letter) in fsa_description_map:
+                print("ERROR - duplicate letter:", letter, "| line:", num + 1)
+                is_error = True
+            tuple = (int(item[0]), letter)
+            fsa_description_map[tuple] = int(item[1])
+
+    if is_error:
+        exit(-1)
+
+states = {}
+for item in fsa_description_map:
+    states[item[0]] = states[item[0]] + item[1] if item[0] in states else item[1]
+
+
+from collections import Counter
+
+
+# check if all letters are used once
+def is_permutation(str1, str2):
+    return Counter(str1) == Counter(str2)
+
+
+def find_missing_letters(str1, str2) -> str:
+    missing_letters = ""
+    for char in str2:
+        if char not in str1:
+            missing_letters += char
+    return missing_letters
+
+
+for state in states:
+    if not is_permutation(states[state], alfabet):
+        print(
+            f"ERROR - state {state} doesn't match: {states[state]} | {alfabet} | diff - {find_missing_letters(states[state], alfabet)}"
+        )
+        exit(-1)
+
+
+with open(join_path(sys.argv[2]), "r", newline="", encoding="utf8") as csvfile:
+    filereader = csv.reader(csvfile, delimiter="\t", quotechar="|")
+    test_in = list(filereader)
+
+with open(join_path(sys.argv[3]), "r", newline="", encoding="utf8") as csvfile:
+    filereader = csv.reader(csvfile, delimiter="\t", quotechar="|")
+    test_out = list(filereader)
+
+
+is_difference = []
+for i, word in enumerate(test_in):
+    current_state = 0
+    if len(word) != 0:
+        for letter in word[0]:
+            current_state = fsa_description_map[(current_state, letter)]
+
+    print(str(i + 1) + "\t", end="")
+    if current_state == accepting_state:
+        print("YES\t", end="")
+        if "YES" != test_out[i][0]:
+            print("ERROR", word, end="")
+            is_difference.append(i)
+    else:
+        print("NO\t", end="")
+        if "NO" != test_out[i][0]:
+            print("ERROR", word, end="")
+            is_difference.append(i)
+    print()
+
+if len(is_difference) != 0:
+    print(is_difference)