#include <bits/stdc++.h>
using namespace std;
int main(void) {
  ios_base ::sync_with_stdio(false);
  cin.tie(NULL);
  int n, k;
  cin >> n >> k;
  if (k == 1) {
    cout << "a";
  } else if (k == 2) {
    cout << "ab";
  } else if (k == 3) {
    cout << "abc";
  } else if (k == 4) {
    cout << "abcd";
  } else if (k == 5) {
    cout << "abcde";
  } else if (k == 6) {
    cout << "abcdef";
  } else if (k == 7) {
    cout << "abcdefg";
  } else if (k == 8) {
    cout << "abcdefgh";
  } else if (k == 9) {
    cout << "abcdefghi";
  } else if (k == 10) {
    cout << "abcdefghij";
  } else if (k == 11) {
    cout << "abcdefghijk";
  } else if (k == 12) {
    cout << "abcdefghijkl";
  } else if (k == 13) {
    cout << "abcdefghijklm";
  } else if (k == 14) {
    cout << "abcdefghijklmn";
  } else if (k == 15) {
    cout << "abcdefghijklmno";
  } else if (k == 16) {
    cout << "abcdefghijklmnop";
  } else if (k == 17) {
    cout << "abcdefghijklmnopq";
  } else if (k == 18) {
    cout << "abcdefghijklmnopqr";
  } else if (k == 19) {
    cout << "abcdefghijklmnopqrs";
  } else if (k == 20) {
    cout << "abcdefghijklmnopqrst";
  } else if (k == 21) {
    cout << "abcdefghijklmnopqrstu";
  } else if (k == 22) {
    cout << "abcdefghijklmnopqrstuv";
  } else if (k == 23) {
    cout << "abcdefghijklmnopqrstuvw";
  } else if (k == 24) {
    cout << "abcdefghijklmnopqrstuvwx";
  } else if (k == 25) {
    cout << "abcdefghijklmnopqrstuvwxy";
  } else if (k == 26) {
    cout << "abcdefghijklmnopqrstuvwxyz";
  }
  for (int i = 0; i < (n - k); i++) {
    if (i % 2 == 0) {
      cout << "a";
    } else {
      cout << "b";
    }
  }
  return 0;
}
