#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,d,e;
	cin>>a;
	b=a%10;
	c=a/10%10;
	d=a/100%10;
	if(b<c){
		swap(b,c);
	}
     if(b<d){
		swap(b,d);
	}
    if(c>d){
		swap(c,d);
	}
	e=b-c;
	cout<<e;
}
/**************************************************************
	Problem: 1667
	User: toughuatao1
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/