#include<iostream>
using namespace std;
unsigned nr;
int a,b,c;
int main()
{
cin>>nr;
a=nr/100;
b=nr%100/10;
c=nr%10;
if((a>b)&&(b<c))
if(a>c)
cout<<c;
else
cout<<a;
if((a<b)&&(b>c))
if(a<c)
cout<<c;
else
cout<<a;
if((a<b)&&(b<c))
cout<<b;
if((a>b)&&(b>c))
cout<<b;
return 0;
}