#include <bits/stdc++.h>
using namespace std;
int main() {
  char A = 'a', last_char;
  int N, K;
  cin >> N >> K;
  string s = "";
  for (int i = 0, j = 1; j <= N; j++, i++) {
    s += (A + i);
    if (K == (i + 1)) i = -1;
  }
  cout << s;
}
