#include<bits/stdc++.h>
using namespace std;
int main() { 
  int a,b,c,d;
  cin>>a>>b>>c>>d;
  if (a>b) swap(a,b);
  if (a>c) swap(a,c);
  if (a>d) swap(a,d);
  if (b>c) swap(b,c);
  if (b>d) swap(b,d);
  if (c>d) swap(c,d);
   
  cout<<d;
   
    return 0;
}
/**************************************************************
	Problem: 1305
	User: suziqian
	Language: C++
	Result: Accepted
	Time:16 ms
	Memory:2072 kb
****************************************************************/