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