#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,i=0,v=0,z=0,a=0,m=0,s=0;
    cin>>n;
        i=n%10;
        v=n%100/10;
        z=n%1000/100;
        a=n/1000;
        m=i*1000+v*100+z*10+a;
        s=n-m;
        cout<<s;
    }
/**************************************************************
	Problem: 1702
	User: linyuhang
	Language: C
	Result: Compile Error
****************************************************************/