#include <stdio.h>

int main() {
    int n1, n2, n3, n4, tomadas;
    scanf("%d", &n1);
    scanf("%d", &n2);
    scanf("%d", &n3);
    scanf("%d", &n4);

    tomadas = (n1+n2+n3+n4)-3;
    printf("%d", tomadas);
    return 0;
}