#include <stdio.h>

int main() {
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    int max = a;
    if(b > max)
        max = b;
    if(c > max)
        max = c;
    if(d > max)
        max = d;
    printf("%d", max);
    return 0;
}