백준 #2475번 검증수

import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();
		int d = sc.nextInt();
		int e = sc.nextInt();
		int f;
		
		f = (a * a + b * b + c * c + d * d + e * e) % 10;
		System.out.println(f);
		sc.close();
	}
}