import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Scanner;

class Main {

	public static void main(String[] args) {
		new Main().run();
	}
	
	void run() {
		Scanner sc = new Scanner(System.in);
		int n=sc.nextInt();
		long[] P=new long[n];
		boolean zero=false;
		for(int i=0;i<n;++i) {
			P[i]=sc.nextLong();
			zero|=P[i]==0;
		}
		if(zero) {
			System.out.println(0);
			return;
		}
		long ans=1;
		for(int i=0;i<n;++i) {
			ans=ans*(P[i]%9)%9;
		}
		if(ans==0)ans=9;
		System.out.println(ans);
		
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
}