d задача

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <algorithm>
#include <set>
#include <list>
#include <sstream>
#include <vector>
#include <map>
#include <stdlib.h>

using namespace std;
ifstream in("input.txt");
ofstream out("output.txt");


int main() {
    string h;
    int n;
    string alph = "";
    for (char i = 'a'; i < 'z'; i++) {
        alph += i;
    }
    cin >> n >> h;
    string j = "";
    for (int i = 0; i < n-2; i++) {
        if (h[i + 2] == '0' && (i+2) < n) {
            string x(1, h[i]);
            string k(1, h[i + 1]);
            int c = stoi(x + k);
            j += alph[c - 1];
            i+=2;
        }
        else {
            string x(1, h[i]);
            int c = stoi(x);
            j += alph[c - 1];
        }
    }
    cout << j << endl;
}