#include<stdio.h>
int main()
{
    int m,n;
    int u,v;
    
    scanf("%d %d",&m,&n);
    scanf("%d %d",&u,&v);
    
    if(n==0)
    {
        printf("Invalid Input");
    }
    else if(1<=u&&v<=n)
    {
        printf("%d",&u);
    }
    else if(1<=n<=100)
    {
        pritnf("%d",&n);
    }
    else
    {
        pritnf("%d",&m)
    }
    return 0;
}