int max(int a, int b){
    return a > b? a:b;
}

int main() {
    int a,b,c,d;
    cin >> a >>b >>c>>d;
    
    int sol = max(a, b);
    sol  = max(sol, c);
    sol = max(sol, d);
    
    cout << sol;
    return 0;
}