#include <bits/stdc++.h>
#define dbg(i,j) cout<<"I am "<<i<<" = "<<endl<<j<<endl;
#define dbr(name,a) cout<<name<<endl;for(auto x:a)cout<<x<<" ";cout<<endl;
#define DBR(name,a) cout<<name<<endl;for(auto x:a){ for(auto y:x)cout<<y<<" ";cout<<endl;}
#define dbmp(name,a) cout<<name<<endl;for(auto x:a){ cout<<x.first<<"\t"<<x.second<<endl;}
#define dbp(name,a) cout<<name<<endl;cout<<a.first<<"\t"<<a.second<<endl;
#define boost ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;

typedef long long int big;

typedef  long double fig;

int main(){
    big n;
    cin>>n;
    vector<big> arr(n);
    map<big,big> count;
    for(big i=0;i<n;i++){
        cin>>arr[i];
    }
    big start=0,end=0,now=0,l=0;
    big a=0,b=0,diff=0;
    for(big i=0;i<n;i++){
        count[arr[i]]++;
        if(count[arr[i]]==1){
            now++;
            if(now<=1){
                a=arr[i];
                b=arr[i];
            }
            else if(now>1){
                b=arr[i];
            }
        }
        while(now>2){
            diff=abs(a-b);
            a=0,b=0;
            count[arr[l]]--;
            if(count[arr[l]]==0){
                now--;
            }
            l++;
        }

        if((diff<=1) && i-l+1>=end-start+1){
            end=i,start=l;
        }


    }
    /*for(big i=start;i<=end;i++){
        cout<<arr[i]<<" ";
    }*/
    cout<<(end-start+1)<<endl;
    return 0;
}