#include <bits/stdc++.h>
using namespace std;
set<long long> s;
set<long long>::iterator it;
long long n;
void bfs() {
  queue<long long> q;
  q.push(4);
  q.push(7);
  long long num;
  while (!q.empty()) {
    num = q.front();
    q.pop();
    if (num > 150000) return;
    s.insert(num);
    q.push(num * 10 + 4);
    q.push(num * 10 + 7);
  }
}
int main() {
  cin >> n;
  string st;
  st.resize(n + 2);
  st[n] = '\0';
  long long i, cnt = 0, nextlucky, currpos;
  char c = 'a';
  for (i = 0; i < n; i++) st[i] = '0';
  bfs();
  while (cnt < n) {
    for (i = 0; i < n; i++) {
      if (st[i] == '0') {
        st[i] = c;
        cnt++;
        nextlucky = *(s.upper_bound(0));
        currpos = i;
        while (currpos + nextlucky < n) {
          if (st[currpos + nextlucky] == '0') {
            st[currpos + nextlucky] = c;
            currpos += nextlucky;
            cnt++;
          } else
            nextlucky = *(s.upper_bound(nextlucky));
        }
        c++;
      }
    }
  }
  for (i = 0; i < n; i++) cout << st[i];
  return 0;
}
