#include<stdio.h>
int main()
{
    int m,n,t;
    scanf("%d",&m);
    n=m/10;
    t=m%10;
    if(n>t)
        printf("%d",n);
    else
        printf("%d",t);
    return 0;
}

/**************************************************************
	Problem: 1622
	User: admin
	Language: C
	Result: Accepted
	Time:11 ms
	Memory:1144 kb
****************************************************************/