#include<bits/stdc++.h>

using namespace std;

vector<int> grph[10000];
int node, edge;
int level[10000];
int visited[10000];


int BFS(int source, int destination){
    visited[source] = 1;
    level[source] = 0;

    queue<int> q;
    q.push(source);
    while(!q.empty()){
        int x = q.front();
        q.pop();
        for(int i = 0; i < grph[x].size(); i++){
            int y = grph[x][i];
            if(visited[y] == 0){
                visited[y] = 1;
                if(level[y] == 0){
                    level[y] = level[x] + 1;
                    q.push(y);
                }

            }
        }
    }
    return level[destination];
}


int main(){
    return 0;
}