C++ :

#include <iostream> 
#include <cstdio>
using namespace std;
int main()
{
	int n,ge,shi,bai,qian,ans;
	cin>>n;
	ge=n%10;
	shi=n/10%10;
	bai=n/100%10;
	qian=n/1000;
	ans=ge+shi+bai+qian;
	cout<<ans;
	return 0;
}