from typing import NamedTuple


class R(NamedTuple):
    o: int
    t: int


def fun(a):
    r = []
    for i, ai in enumerate(a):
        t = abs(s - ai)
        if t <= k:
            r += [R(1 + i, t)]

    r = sorted(r, key=lambda x: x.o)
    r = sorted(r, key=lambda x: x.t)

    if len(r) > 0:
        return r[0].o
    return "Unlucky!"


n, s, k = map(int, input().split())
a = [int(input()) for _ in range(n)]
print(fun(a))