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

int main()
{
	int n, s, k;
	cin >> n >> s >> k;
	vector<int> check(n);
	int a;
	for(int i = 0; i < n; i++)
	{
		cin >> a;
		check[i] = abs(a - s);
	}
	
	int ans = 0;
	int minc = 100;
	for(int i = 0; i < n; i++)
	{
		if(k < check[i]) continue;
		if(check[i] < minc)
		{
			ans = i + 1;
			minc = check[i];
		}
	}
	if(ans == 0) cout << "Unlucky!" << endl;
	else cout << ans << endl;
	return 0;
}