#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int a;
  cin >>a;
  int b =a/100;
  int c=a/10-b*10;
  int d=a-b*100-c*10;
  
  int e=min(b, (min(c, d)));
  int f=max(b, (max(c, d)));
  cout << f-e;
}