#include <iostream>
using namespace std;
int main(){
    int n,m,k;cin>>n>>m>>k;
    int dist = k+1;
    int ans = -1;
    for(int i = 0; n > i; i++){
        int x;cin>>x;
        if(m-k <= x && x <= m+k){
            if(dist > abs(x-m)){
                dist = abs(x-m);
                ans = i+1;
            }
        }
    }
    if(ans == -1){
        cout << "Unlucky!" << endl;
    }else{
        cout << ans << endl;
    }
}