include

include

using namespace std;

int max_of_four(int a, int b, int c, int d){ int max = 0;

    if (a >= max){
        max = a;
    }
    if (b >= max){
        max = b;
    }
    if (c >= max){
        max = c;   
    }
    if (d >= max){
        max = d;
    }
    return max;

}

int main() { int a, b, c, d; scanf("%d %d %d %d", &a, &b, &c, &d); int ans = max_of_four(a, b, c, d); printf("%d", ans);

return 0;

}