A = list(map(int, input().split()))
s = True
res = 0
while s:
    k = False
    c = 0
    for i in range(1, len(A)):
        if A[i] == A[i - 1] and i != len(A) - 1:
            c += 1
        elif i == len(A) - 1 and A[i] == A[i - 1] and c >= 2:
            c += 1
            n = A[i - 1]
            for j in range(c + 1):
                A.remove(n)
            res += c + 1
            k = True
            break
        elif c >= 2:
            n = A[i - 1]
            for j in range(c + 1):
                A.remove(n)
            res += c + 1
            k = True
            break
        else: c = 0
    s = k
print(res)