#include <stdio.h>

int main() 
{
    int arr[4];
    int max;
    for(int i = 0; i<4; i++)
    {
        scanf("%d",&arr[i]);
        if(0 == i)
        {
            max = arr[i];
        }
        else if(0 != i && max < arr[i])
        {
            max = arr[i];
        }
    }
    printf("%d", max);
}