//In the name of Allah the most beneficent, the most merciful.
#include <bits/stdc++.h>
using namespace std;
// #pragma GCC optimize("Ofast,unroll-loops")
// #pragma GCC target("avx,avx2,avx512,fma")
#define int long long
#define ar array
#define ll long long
#define ld long double
#define sza(x) ((int)x.size())
#define all(a) (a).begin(), (a).end()
#define PI 3.1415926535897932384626433832795l
const int N = 5005;
const ll MOD = 1e9 + 7;
const ll INF = 1e9;
const ld EPS = 1e-9;
// -------------------------<RNG>-------------------------
// RANDOM NUMBER GENERATOR
mt19937 RNG(chrono::steady_clock::now().time_since_epoch().count());
#define SHUF(v) shuffle(all(v), RNG);
// Use mt19937_64 for 64 bit random numbers.
//--------------------------------------------------------
vector<int> adj[N];
int e1,e2;
bool vis[N];
int n,m;
void dfs(int node){
vis[node]=1;
for(auto i:adj[node]){
if((node==e1&&i==e2) || (node==e2&&i==e1))
continue;
if(!vis[i])
dfs(i);
}
}
bool check(pair<int,int> e){
e1=e.first;
e2=e.second;
for(int i=0;i<=n;i++)
vis[i]=0;
dfs(e1);
return !(vis[e2]);
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin>>n>>m;
vector<pair<int,int>> ed;
for(int i=0;i<m;i++){
int a,b;
cin>>a>>b;
adj[a].push_back(b);
adj[b].push_back(a);
ed.push_back(make_pair(a,b));
}
for(auto e:ed)
if(check(e))
cout<<e.first<<' '<<e.second<<endl;
}
