#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int N,S,K;
  cin>>N>>S>>K;
  int ans = -1;
  int best = K+1;
  for(int i=1;i<=N;i++){
      int x;
      cin>>x;
      if(abs(x-S) < best){
          best = abs(x-S);
          ans = i;
      }
  }
  if(ans>0) cout<<ans<<endl;
  else cout<<"Unlucky!"<<endl;
}