#include <bits/stdc++.h>
using namespace std;

int main() {
  int n, s, k;
  cin >> n >> s >> k;
  const int inf = (int)1e9;
  int min_diff = inf;
  int ans = -1;
  for (int i = 0; i < n; i++) {
    int a;
    cin >> a;
    int diff = abs(a - s);
    if (diff < min_diff && diff <= k) {
      min_diff = diff;
      ans = i + 1;
    }
  }
  if (ans == -1)
    puts("Unlucky!");
  else
    cout << ans << '\n';
  return 0;
}