#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;

int N, S, K, M = 1e9, ans = -1;
int A[11];
int main() {
  cin >> N >> S >> K;
  for (int i = 1; i <= N; i++) {
    cin >> A[i];
    if (abs(A[i] - S) <= K) {
      if (M > abs(A[i] - S)) {
        M = abs(A[i] - S);
        ans = i;
      }
    }
  }
  if (ans == -1) cout << "Unlucky!" << endl;
  else cout << ans << endl;
  return 0;
}