#include <stdio.h>

int main()
{
    int arr[4] = { 0 };

    for (int i = 0; i < 4; i++)
    {
        scanf("%d", &arr[i]);
    }
    int max = arr[0];
    for (int i = 1; i < 4; i++)
    {
        max = max > arr[i] ? max : arr[i];
    }
    printf("%d\n", max);

    return 0;
}