https://codeforces.com/group/n3sTiYtHxI/contest/348734/problem/S

#include <iostream>
#include<bits/stdc++.h>
#define ll long long
using namespace std;

void  sum( long long a ){
  long long s = 0;
 while(a>0){
     s= s+(a%10);
     a/=10;
 }
 cout<<s;
 }

int main() {
   ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

long long n,a; cin>>n>>a;
 sum(a);

    return 0;
}