#include <iostream>
#include <string>
#include <queue>
#include <algorithm>
#include <vector>

using namespace std;
#define X first
#define Y second

string borad[50];
bool vis[52][52];

int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    vector<int> res;
    int n,cnt=0;
    queue<pair<int,int>> q;
    cin >> n;
    for(int i=0; i<n; i++) cin >> borad[i];

    for(int i=0; i<n; i++) {
        for(int j=0; j<n; j++) {
            if(borad[i][j]=='0' || vis[i][j]) continue;

            cnt++;
            q.push({i,j});
            vis[i][j]=1;
            int area=0;
            while(!q.empty()) {
                area++;
                pair<int,int> cur=q.front();
                q.pop();

                for(int idx=0; idx<4; idx++) {
                    int nx=cur.X+dx[idx];
                    int ny=cur.Y+dy[idx];
                    if(nx<0 || nx>=n ||ny<0 || ny>=n) continue;
                    if(vis[nx][ny] || borad[nx][ny]=='0') continue;

                    vis[nx][ny]=1;
                    q.push({nx,ny});
                }
            }
            res.push_back(area);
        }
    }
    sort(res.begin(),res.end());
    cout << cnt << '\n';
    for (int x:res) cout << x << '\n';
}