#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, length = 1, i = 0;
  scanf("%d%d", &n, &k);
  string pass = "a";
  while (length < n) {
    if (length < k) {
      pass += (char)((int)pass[pass.length() - 1] + 1);
      length++;
    } else {
      if (i == k) i = 0;
      pass += pass[i];
      length++;
      i++;
    }
  }
  cout << pass;
}
