https://www.acwing.com/problem/content/description/1479/

#include <iostream>

using namespace std;

int main () {
    string st;
    cin >> st;
    int sum = 0;
    for (auto c : st) sum += c - '0';

    string nums[] = {
        "zero","one","two","three","four",
        "five","six","seven","eight","nine"
    };

    st = to_string(sum);

    for (auto c : st)  {
        int v = c - '0';
        cout << nums[v] << ' ';
    }
    return 0;
}