N, S, K = map(int, input().split())

ret = 100000
reti = -1
A = [int(input()) for _ in range(N)]
for idx, a in enumerate(A):
    if abs(a - S) < abs(a - ret):
        ret = a
        reti = idx + 1

if abs(ret - S) <= K:
    print(idx)
else:
    print("Unlucky!")