n, s, k = map(int, input().split())

d_min = 114514
i_min = -1

for i in range(n):
    a = int(input())

    if d_min > abs(a - s):
        d_min = abs(a - s)
        i_min = i

print(i_min + 1 if d_min <= k else "Unlucky!")