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