#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<cctype>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define LINF (ll)INF*INF
#define MOD 1000000007
#define rep(i,n) for(int i=0;i<(n);i++)
#define loop(i,a,n) for(int i=a;i<(n);i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

#define int ll //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int,int> pii;
typedef vector<pii> vp;

int gcd(int a, int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int lcm(int a, int b){
    return a/gcd(a,b)*b;
}


signed main(void) {
    int n;
    while(cin >> n,n){
        vs s(n);
        rep(i,n)cin >> s[i];
        int ans = 0;
        rep(i,n)rep(j,n)if(s[i][j] == '1'){
            int k = j;
            while(k < n && s[i][k] == '1')k++;
            ans = max(ans, k-j);
            k = i;
            while(k < n && s[k][j] == '1')k++;
            ans = max(ans, k-i);
            k = 0;
            while(i+k < n && j+k < n && s[i+k][j+k] == '1')k++;
            ans = max(ans, k);
            k = 0;
            while(i+k < n && j-k >= 0 && s[i+k][j-k] == '1')k++;
            ans = max(ans, k);
            //cout << i << " " << j << " " << ans << endl;
        }

        cout << ans << endl;
    }

}

