47

def f(lst):
  for i in range(len(lst)-2):
      if lst[i] == lst[i+1] == lst[i+2]:
          return True
def ff(spisok):
  max_len = 0
  cur_len = 0
  for i in range(1, len(spisok)):
    if spisok[i] == spisok[i-1]:
      cur_len += 1
    else:
      cur_len = 1
    if cur_len > max_len:
       max_len = cur_len
  return max_len
lst = list(map(int, input().split()))
s = 0
ans = 0
while f(lst) == True:
  for i in range(len(lst)-2):
      if lst[i] == lst[i+1] == lst[i+2]:
          s = lst[i]
          for el in range(ff(lst)):
              lst.pop(i)
              ans += 1
          break
print(ans)