N = int(input())
A = [int(a) for a in input().split()]

dp0 = [0]*N #i番目をずんだ餅にした時のずんだ餅の個数の最大値
dp1 = [0]*N #i番目をずんだ餅にしなかった時のずんだ餅の個数の最大値
dp0[0] = 1
for i in range(1, N):
    if A[i-1] == A[i]:
        dp0[i] = max(dp0[i-1]+1, dp1[i-1]+1)
        dp1[i] = max(dp0[i-1], dp1[i-1])
    else:
        dp0[i] = max(dp0[i-1], dp1[i-1]+1)
        dp1[i] = max(dp0[i-1], dp1[i-1])

print(max(dp0[N-1], dp1[N-1]))