func_code_string: #include <bits/stdc++.h>   using namespace std;   void solve() {     long long int n, k;     cin >> n >> k;     if (k > n)       cout << -1 <<   n ;     else if (n != 1 && k == 1)       cout << -1 <<   n ;     else if (k == n) {       char x =  a ;       for (long long int i = 1; i <= (long long int)n; i++) {         cout << x;         x++;       }     } else if (k < n) {       long long int t = n - (k - 2);       for (long long int i = 1; i <= (long long int)t; i++) {         if (i % 2 != 0)           cout <<  a ;         else           cout <<  b ;       }       long long int q = n - t;       char y =  c ;       if (q > 0) {         for (long long int i = 1; i <= (long long int)q; i++) {           cout << y;           y++;         }       }     }   }   int main() {     std::ios::sync_with_stdio(false);     int t = 1;     while (t--) {       solve();     }     return 0;   }   