import java.util.LinkedList;
import java.util.Queue;

public class Main {
	
	public static void main(String[] args) {
		
		String input = args[0];
		
		String[] parts = input.split(" ");
		
		// n
		int mod = Integer.parseInt(parts[0]);
		//int number = Character.getNumericValue(numberStr.charAt(0));
		
		String polynomialStr = parts[1];
		
		// usuwam '[', ']'
		polynomialStr = polynomialStr.substring(1, polynomialStr.length()-1);
		
		// ,
		String[] polynomialNumbers = polynomialStr.split(",");
		
		LinkedList<Integer> polynomial = new LinkedList<Integer>();
		
		//test poly
		LinkedList<Integer> polynomial2 = new LinkedList<Integer>();
		
		// wypelnienie wielomianu
		polynomial = fill(polynomialNumbers, polynomial);
		
		//test
		LinkedList<LinkedList<Integer>> elements = new LinkedList<LinkedList<Integer>>();
		elements = createCandidates(polynomial,mod);
		
		// Idemp
		System.out.println(idempotent(elements,polynomial,mod));
		
		//showPoly(polynomial);
	}

	// wypelnienie wielomianu
	public static LinkedList<Integer> fill(String[] str, LinkedList<Integer> polynomial){
		
		for(int i=0; i <str.length; i++) {
			polynomial.add(Integer.parseInt(str[i]));
		}
		
		return polynomial;
	}
	
	
	public static void showPoly(LinkedList<Integer> poly) {
		System.out.println(poly.toString());
	}


	public static int multiplier(int number, int expect, int mod) {
		
		/*
		if(nwd(number,mod) != 1 || nwd(number,mod) != number) {
			System.out.println("NIE DA SIE");
			return 0;
		}*/

		for(int i=1;i<mod;i++) {
			if(((number*i) % mod) == expect) {
				return i;
			}
		}
		return 0;
	}


	public static LinkedList<Integer> modPolynomial(int mod, LinkedList<Integer> polynomial){
		
		LinkedList<Integer> result = new LinkedList<Integer>();
		
		while(!polynomial.isEmpty()) {
			
			if(polynomial.peek() < 0) {
				
				result.add(mod + polynomial.poll());
			}
			else result.add(polynomial.poll() % mod);
		}
		return result;
	}
	
}