#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  char ans[n];
  for (int x = 0; x < k; x++) {
    ans[x] = 97 + x;
    cout << ans[x];
  }
  for (int x = k; x < n; x++) {
    ans[x] = 97 + (x % 2);
    cout << ans[x];
  }
}
