#include <stdio.h>

int main() {
   int a,b,c,d;
   scanf("%d %d %d %d",&a,&b,&c,&d);
   int MAX =(a>b)?a:b;
   MAX = (MAX > c)?MAX:c;
   MAX = (MAX > d)?MAX:d;
   printf("%d",MAX);
    return 0;
}