#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: toughuatao1
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/