#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int max(int x,int y)
{
    if(x>y)
    return x;
    else
    return y;
}

int main()
{
    int a,b,c,d;
    scanf("%d %d %d %d\n",&a,&b,&c,&d);
    printf("%d",max(max(a,b),max(c,d)));
    return 0;
}