#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b,c,d,e,f;
    cin>>a;
    b=a%10;
    c=a/10%10;
    d=a/100%10;
    e=a/1000%10;
    f=b*1000+c*100+d*10+e;
    cout<<a-f;
}
/**************************************************************
	Problem: 1702
	User: tonghuawei
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/