S = [int(s) for s in input().split()]
n = len(S)

ans = 0

for i in range(n - 2):
    if len(set(S[i : i + 3])) == 2 and (S[i] == S[i + 1] or S[i + 1] == S[i + 2]):
        ans += 1

print(ans)