package main

import (
    "fmt"
)

func Abs(a, b int) int{
    if a >b{
        return a-b
    }
    return b-a
}

func main() {
    var n int
    fmt.Scan(&n)
    var k = make([]int, n+1) // 多一个
    for i:=0;i<n;i++{
        fmt.Scanf("%d", &k[i])
    }
    k[n]=-2 // -2-0>1,确保k最后的稳定部分计算进去
    var left, right, max int = 0,1,1
    for right <= n{
        if Abs(k[right], k[right-1]) > 1{
            if max < right - left{
                max = right - left
            }
            left = right
            right++
        }else{
            right++
        }
    }
    fmt.Print(max)
}