#include <bits/stdc++.h>
using namespace std;
int main() {
long long a, b, c, d;
cin >> a >> b >> c >> d;
long long max_num = a;
if ( b > max_num ) {
max_num = b;
}
if ( c > max_num ) {
max_num = c;
}
if ( d > max_num ) {
max_num = d;
}
cout << max_num << endl;
return 0;
}
I2luY2x1ZGUgPGJpdHMvc3RkYysrLmg+CnVzaW5nIG5hbWVzcGFjZSBzdGQ7CgppbnQgbWFpbigpIHsKCWxvbmcgbG9uZyBhLCBiLCBjLCBkOwoJY2luID4+IGEgPj4gYiA+PiBjID4+IGQ7Cglsb25nIGxvbmcgbWF4X251bSA9IGE7CglpZiAoIGIgPiBtYXhfbnVtICkgewoJCW1heF9udW0gPSBiOwoJfQoJaWYgKCBjID4gbWF4X251bSApIHsKCQltYXhfbnVtID0gYzsKCX0gCglpZiAoIGQgPiBtYXhfbnVtICkgewoJCW1heF9udW0gPSBkOwoJfQoJY291dCA8PCBtYXhfbnVtIDw8IGVuZGw7CglyZXR1cm4gMDsKfQ==