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

int main() {
    int N, S, K; cin >> N >> S >> K;
    int idx = -1;
    int diff = K + 1;
    for(int i = 1; i <= N; i++) {
        int a; cin >> a;
        if(abs(a - S) < diff) {
            idx = i;
            diff = abs(a - S);
        }
    }
    if(idx == -1) {
        cout << "Unlucky!" << endl;
    } else {
        cout << idx << endl;
    }
    return 0;
}