#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#define endl '\n'
using namespace std;

typedef long long ll;

int main() {
	int l, r;
	cin >> l >> r;
	string s = " atcoder";
	for (int i = l; i <= r; i++)
		cout << s[i];
	return 0;
}