---

N = int(input())
M = int(input())
X = int(input())
beads = [int(input()) for _ in range(N)]

count = 0
left = 0
favorite_count = 0
for right in range(N):
    if beads[right] == X:
        favorite_count += 1
    while favorite_count > 1:
        if beads[left] == X:
            favorite_count -= 1
        left += 1
    if favorite_count == 1:
        count += right - left + 1

count_no_X = 0
left = 0
for right in range(N):
    if beads[right] == X:
        left = right + 1
    count_no_X += right - left + 1

print(count - count_no_X)