#include <bits/stdc++.h>
using namespace std;
int main(){

	int i,e,b,c,d,x,y;
	cin>>i;
	e=i/1000%10;
	b=i/100%10;
	c=i/10%10;
	d=i%10;
	x=d*1000+c*100+b*10+e;
	y=i-x;
	cout<<y;
	
	return 0;
}
/**************************************************************
	Problem: 1702
	User: huangyaojie3
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/