MOD = 10 ** 9 + 7
INF = 10 ** 10
import sys
sys.setrecursionlimit(100000000)
dy = (-1,0,1,0)
dx = (0,1,0,-1)
from collections import deque
from heapq import heapify,heappush,heappop

def main():
    n = int(input())
    a = list(map(int,input().split())) + [-1]

    dp = [[0] * 2 for _ in range(n)]
    
    dp[0][0] = 0
    dp[0][1] = 1
    for i in range(1,n):
        if a[i] == a[i - 1]:
            dp[i][1] = dp[i - 1][1] + 1
            dp[i][0] = dp[i - 1][1]
        else:
            dp[i][1] = dp[i - 1][0] + 1
            dp[i][0] = dp[i - 1][1]
    
    print(max(dp[-1]))

if __name__ =='__main__':
    main()