// Author: HarshKumar

#include <bits/stdc++.h>
using namespace std;
#define ll int64_t
const ll N = 1e6 + 6, M = 1e9 + 7;
int main()
{
    ios::sync_with_stdio(false), cin.tie(nullptr);
    ll n, k;
    cin >> n >> k;
    ll x = min(k * k + 1, n);
    string s(x, 'a');
    map<char, ll> f;
    for (ll i = 0; i < k; i++)
        f['a' + i] = i;
    for (ll i = 1; i < x; i++)
        s[i] = 'a' + f[s[i - 1]] % k, f[s[i - 1]]++;
    s.erase(s.begin());
    cout << 'a';
    n--;
    x--;
    for (ll i = 0; i < n; i++)
        cout << s[i % x];
}