#include<stdio.h>
int main()
{
    int arr[4] = {0};
    int i = 0;
    for(i=0;i<4;++i)
    {
        scanf("%d",&arr[i]);
    }
    int max = arr[0];
    for(i=0;i<4;++i)
    {
        if(arr[i] > max)
            max = arr[i];
    }
    printf("%d\n",max);
    return 0;
}