题解 | #定位查找#

while True:
    try:
        n = int(input())

        nums = list(map(int, input().split()))

        a = int(input())
        i = 0
        for num in nums:
            if num == a:
                print(i)
                break
            i += 1
        else:
            print("No")
    except:
        break