# coding: utf-8
# Your code here!

import sys
sys.setrecursionlimit(10**6)
readline = sys.stdin.readline 

n = int(input())
a = [int(i) for i in readline().split()]


dp1 = 1 #前がずんだ
dp2 = 0 #前がふつう
for i,ai in enumerate(a):
    if i:
        if ai == a[i-1]:
            dp1,dp2 = max(dp1,dp2)+1, max(dp2,dp1)
        else:
            dp1,dp2 = dp2+1,max(dp2,dp1)
#    print(dp1,dp2)

print(max(dp1,dp2))