Balls

a = [int(x) for x in input().split()]
n = a[0]
a.pop(0)

stack = []
ans = i = 0
while i < n:
  x = a[i]
  if len(stack) == 0:
    stack.append( [x, 1] )
  elif stack[-1][0] == x:
    stack[-1][1] += 1
  else:
    y = stack[-1]
    if y[1] > 2:
      stack.pop()
      ans += y[1]
      continue
    stack.append( [x, 1] )
  i += 1

if stack[-1][1] > 2:
  ans += stack[-1][1]
print(ans)