from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N,S,K = map(int,input().split())
A = [int(input()) for _ in range(N)]
X = [(abs(A[i]-S),i) for i in range(N)]
X.sort()
if X[0][0]<=K:
    print(X[0][1]+1)
else:
    print('Unlucky!')