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

int main()
{
	int N, S, K;
	cin >> N >> S >> K;
	typedef pair<int, int> P;
	vector<P> v;
	for( int i = 0; i < N; i++ ) {
		int A;
		cin >> A;
		int a = abs( A - S );
		if( a > K ) continue;
		v.push_back( P( a, i + 1 ) );
	}

	if( (int)v.size() == 0 ) {
		cout << "Unlucky!" << endl;
		return 0;
	}
	sort( v.begin(), v.end() );
	int ans = v[0].second;

	cout << ans << endl;
}