#include<iostream>
#include<cstring>
#include<string>
using namespace std;

class Graph{
private:
    int **matrix;
    int vexnum;
    string *name;
public:
    Graph(string str[], int vnum){
        vexnum = vnum;
        name = new string[vexnum];
        for(int i = 0; i < vexnum; i++)
            name[i] = str[i];
        matrix = new
 
 int*[vnum];
        for (int i = 0; i < vexnum; i++) {
            matrix[i] = new int [vexnum];
            for (int j = 0; j <vexnum; j++)
                cin>>matrix[i][j];
        }

    }
    void floyd(){
        string **path = new string*[vexnum];
        for(int i = 0; i<vexnum;i++) {
            path[i] = new
 
 string[vexnum];
            for (int j = 0;j<vexnum;j++)
                if(i==j)
                    path[i][j] = name[i];
                else
                    path[i][j] = name[i]+name[j];
        }
        int dis[vexnum][vexnum];
        for(int i = 0; i<vexnum;i++)
            for (int
 
 j=0; j <vexnum;j++)
                dis[i][j] = matrix[i][j];
        for(int k = 0; k < vexnum; k++)
            for(int i = 0; i < vexnum; i++)
                for(int j = 0; j <vexnum; j++){
                    if (dis[i][k] == -1||dis[k][j] == -1)
                        continue;
                    if (i!=j){
                        if(dis[i][j] == -1 || dis[i][j]>dis[i][k]+dis[k][j]){
                            dis[i][j] = dis[i][k]+dis[k][j];
                            //節點i到j最短路徑為path[i][k]加path[k][j]，中間有重複的k節點，所以要截去
                            path[i][j] = path[i][k].substr(0,path[i][k].length() - 1) + path[k][j];
                        }
                    }
                }
        cout<<vexnum<<endl;
        for (int i = 0; i <vexnum;i++){
            if (i!=0)
                cout<<' ';
            cout<<name[i];
        }
        cout<<endl;
        for(int i = 0;i<vexnum;i++){
            for (int j = 0; j<vexnum;j++){
                if(j!=0)
                    cout<<' ';
                cout<<path[i][j];
            }
            cout<<endl;
        }
    }
};
int main(){
    int n;
    cin>>n;
    string *str = new string[n];
    for(int i = 0;i<n;i++)
        cin>>str[i];
    Graph G(str,n);
    G.floyd();
    return 0;
}

/*測試資料（有向圖）
 輸入
 4
 a b c d
 0 1 -1 7
 2 0 2 -1
 -1 -1 0 2
 1 3 -1 0

 輸出
 4
 a b c d
 a ab abc abcd
 ba b bc bcd
 cda cdab c cd
 da dab dabc d

*/