n, s, k = map(int, input().split())
a = [int(input()) for _ in range(n)]
res, cnt = 0, k+1
for i in range(n):
    if abs(a[i] - s) <= k and abs(a[i] - s) < cnt:
        cnt = abs(a[i] - s)
        res = i + 1
print(res if res else "Unlucky!")