#include <bits/stdc++.h>
using namespace std;

struct edge
{
    int a;
    int b;
};

void sol(vector<string> id, vector<edge> edges)
{
    int n = id.size(), m = edges.size(), MAX = 1;
    bool flag = true;
    vector<vector<int>> cost;
    cost.resize(n);
    for(int i=0;i<n;i++){
        cost[i].resize(n, INT_MAX);
        cost[i][i] = 0;
    }
    for(int i=0;i<m;i++){
        cost[edges[i].a][edges[i].b] = 1;
        cost[edges[i].b][edges[i].a] = 1;
    }
    for(int i=0;i<(int)cost.size();i++){
        for(int j=0;j<(int)cost.size();j++){
            for(int k=0;k<(int)cost.size();k++){
                if((cost[j][i]+cost[i][k])<cost[j][k]){
                    cost[j][k] = cost[j][i] + cost[i][k];
                }
            }
        }
    }
    for(int i=0;i<(int)cost.size();i++){
        for(int j=0;j<(int)cost.size();j++){
            cout << cost[i][j] << " ";
        }
    }
    for(int i=0;i<(int)cost.size();i++){
        for(int j=0;j<(int)cost.size();j++){
            if(cost[i][j] == INT_MAX){
                flag = false;
                MAX = -1;
                break;
            }
            MAX = max(MAX, cost[i][j]);
        }
        if(!flag){
            break;
        }
    }
    cout << MAX << "\n";
    return;
}

int main()
{
    int n, a, b, idx=0;
    while(cin >> n){
        vector<string> id;
        vector<edge> edges;
        string s1, s2;
        for(int i=0;i<n;i++){
            idx = 0;
            cin >> s1 >> s2;
            for(int j=0;j<(int)id.size();j++){
                if(s1==id[j]){
                    idx += 10;
                    a = j;
                }
                if(s2==id[j]){
                    idx += 1;
                    b = j;
                }
            }
            if(s1==s2 && idx==0){
                a = (int)id.size();
                id.push_back(s1);
                b = a;
            }
            else{
                if(idx==0){
                    a = (int)id.size();
                    id.push_back(s1);
                    b = (int)id.size();
                    id.push_back(s2);
                }
                else if(idx==1){
                    a = (int)id.size();
                    id.push_back(s1);
                }
                else if(idx>1){
                    b = (int)id.size();
                    id.push_back(s2);
                }
                if(a!=b){
                    edges.push_back({a, b});
                }
            }
        }
        sol(id, edges);
    }
    return 0;
}