#include <iostream>
#include<bits/stdc++.h>

using namespace std;
const int N = 100;
int M[N][N];
int visited[N];

int bfs(int s, int t, int count) {
    int queue[count + 2];
    int dp[count + 2];
    for (int i = 0; i < count+2; i++) {
        dp[i] = 0;
        queue[i] = 0;
    }
    int ind = 2, leveasa = 2;
    queue[1] = s;
    dp[s] = 1;
    visited[s] = 1;
    while (queue[1] > 0) {
        int v = queue[1];
        queue[1] = 0;
        for (int i = 1; i < N; i++) {
            if(M[v][i] != 0){
                dp[i] = dp[v] + dp[i];
                cout << dp[i] <<  " " << i << " " << v << endl;
            }
            if (M[v][i] != 0 && visited[i]== 0) {
                queue[ind] = i;
                ind++;
                visited[i] = 1;
                cout << "HUI " << dp[i] <<  " " << i << " " << v << " " << ind << endl;
            }
        }
        queue[1] = queue[leveasa];
        leveasa++;
    }
    return dp[t];
}

int main() {
    int a, b, count, res;
    count = 0;
    ifstream fin("fin.txt");
    while (fin >> a >> b) {
        M[a][b] = 1;
        count = max(max(a, b), count);
    }
    res = bfs( 1, 4, count);
    cout << res << endl;
    return 0;
}