#include <iostream>
using namespace std;

int main()
{
	int val, sum, i;
	int TOTAL = (1 + 13) * 13;
	int N = 26;
	sum = 0;
	for (i = 1; i < N; i++) {
		cin >> val;
		sum += val;
	}
	printf("%d\n", TOTAL - sum);
		return 0;
}