#include <iostream>

using namespace std;
using LL = long long;

int main() {
    int N, S, K;
    cin >> N >> S >> K;

    pair<int, int> ans = make_pair(100, 100);
    int A;
    for (int i = 1; i <= N; i++) {
        cin >> A;
        if (abs(S - A) <= K) {
            if (ans.first > abs(S - A)) {
                ans = make_pair(abs(S - A), i);
            }
        }
    }

    if (ans.second == 100) {
        cout << "Unlucky!" << endl;
    } else {
        cout << ans.second << endl;
    }
}