#include<iostream>
#include<algorithm>
#include<climits>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<ctime>
#include<string>
#include<cstring>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<bitset>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<long long, int> ll_i;

#define PI 3.141592653589793238462643383279
#define mod 1000000007LL
#define rep(i, n) for(i = 0;i < n;++i)
#define rep1(i, n) for(i = 1;i < n;++i)
#define per(i, n) for(i = n - 1;i > -1;--i)
#define int(x) int x; scanf("%d",&x)
#define int2(x, y) int x, y; scanf("%d%d",&x, &y)
#define int3(x, y, z) int x, y, z; scanf("%d%d%d",&x, &y, &z)
#define int4(v, x, y, z) int v, x, y, z; scanf("%d%d%d%d", &v, &x, &y, &z)
#define int5(v, w, x, y, z) int v, w, x, y, z; scanf("%d%d%d%d%d", &v, &w, &x, &y, &z)
#define pri(x) cout << (x) << "\n"
#define pri2(x, y) cout << (x) << " " << (y) << "\n"
#define pri3(x, y, z) cout << (x) << " " << (y) << " " << (z) << "\n"
#define pb push_back
#define mp make_pair
#define all(a) (a).begin(),(a).end()
#define kabe puts("---------------------------")
#define kara puts("")
#define debug(x) cout << " --- " << (x) << "\n"
#define debug2(x, y) cout << " --- " << (x) << " " << (y) << "\n"
#define debug3(x, y, z) cout << " --- " << (x) << " " << (y) << " " << (z) << "\n"
#define X first
#define Y second
#define eps 0.0001
#define prid(x) printf("%.15lf\n", x)

string s[255];
int n;

int solve(bool x){
  int i, j, r, res = 0;
  if(x){
    rep(i, n)for(j = 0;j < n;){
      if(s[i][j] == '0'){ ++j; continue; }
      for(r = j + 1;r < n;++r)if(s[i][r] == '0')break;
      res = max(res, r - j);
      j = r;
    }
  }else{
    rep(i, n){
      for(j = 0;j < n - i;){
        if(s[j][j + i] == '0'){ ++j; continue; }
        for(r = j + 1;r + i < n;++r)if(s[r][r + i] == '0')break;
        res = max(res, r - j);
        j = r;
      }
      for(j = 0;j < n - i;){
        if(s[j + i][j] == '0'){ ++j; continue; }
        for(r = j + 1;r + i < n;++r)if(s[r + i][r] == '0')break;
        res = max(res, r - j);
        j = r;
      }
    }
  }
  return res;
}
void pr(void){
  int i;
  kabe;
  rep(i, n)cout << s[i] << endl;
  return;
}
signed main(void){
  int i, j;
  for(int testcase = 0;testcase >= 0;testcase++){
    scanf("%d", &n);
    if(!n)break;

    rep(i, n)cin >> s[i];

    int res = 0;
    res = solve(1);
    rep(i, n)rep(j, i)swap(s[i][j], s[j][i]);
    res = max(res, solve(1));
    rep(i, n)rep(j, i)swap(s[i][j], s[j][i]);
    res = max(res, solve(0));
    rep(i, n)rep(j, n / 2)swap(s[i][j], s[i][n - j - 1]);
    res = max(res, solve(0));
    pri(res);

//*/

//*/ break;
  }
  return 0;
}