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

int main(){
    int N, K, S, ans = -1, v, d, mn = 1 << 30;
    cin >> N >> K >> S;
    for(int i = 0; i < N; i++){
        cin >> v;
        d = abs(S - v);
        if(d <= K && d < mn){
            mn = d;
            ans = i + 1;
        }
    }
    if(ans == -1)cout << "Unlucky!" << '\n';
    else cout << ans << '\n';
}