A = list(map(int, input().split()))
s = True
res = 0
while s:
    c = 0
    i = 1
    k = False
    while i < 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 >= 1:
            c += 1
            for j in range(c + 1):
                A.pop(i - c)
            k = True
            res += c + 1
            i -= c
            c = 0
        elif c >= 2:
            for j in range(c + 1):
                A.pop(i - c - 1)
            k = True
            res += c + 1
            i -= c + 1
            c = 0
        else:
            c = 0
        i += 1
    s = k
else:
    print(res)