n,s,k = map(int, input().split())
a = [int(input()) for i in range(n)]
ans,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)
        ans = i + 1
if ans: print(ans)
else: print("Unlucky!")