#include<bits/stdc++.h>
using namespace std;
int mian(){
	int n,a,b,c,d,e;
	cin>>n;
	a=n%10;
	b=n/10%10;
	c=n/100%10;
	d=n/1000%10;
	e=a+b+c+d;
	cout<<e;
	return 0;
}

/**************************************************************
	Problem: 1390
	User: linzihang
	Language: C++
	Result: Compile Error
****************************************************************/