text: #include <algorithm>
  #include <iostream>
  #include <cstdio>
  #include <cmath>
  
  using namespace std;
  
  int max_of_four(int a, int b, int c, int d)
  {
  	return max(max(a, b), max(c, d));
  }
  
  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;
  }
  
  