#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 1e5;
const int MAX_LOG_N = 16;
mt19937 rnd(1001);
int n;
int sef[MAX_N + 1], parent[MAX_LOG_N + 1][MAX_N + 1];
bool vis[MAX_N + 1];
vector<int> vert[MAX_N + 1];
int depth[MAX_N + 1];
int sp[MAX_N + 1];
vector<int> adj[MAX_N + 1];
int findSef(int v) {
if (sef[v] != v)
sef[v] = findSef(sef[v]);
return sef[v];
}
bool connect(int u, int v) {
int x = findSef(u);
int y = findSef(v);
if (x == y)
return true;
sef[y] = x;
adj[u].push_back(v);
adj[v].push_back(u);
return false;
}
int lca(int u, int v) {
if (depth[u] > depth[v])
swap(u, v);
for (int l = log2(n); l >= 0; l--) {
if (depth[v] - (1 << l) >= depth[u])
v = parent[l][v];
}
if (u == v)
return u;
for (int l = log2(n); l >= 0; l--) {
if (parent[l][u] != parent[l][v]) {
u = parent[l][u];
v = parent[l][v];
}
}
return parent[0][u];
}
void dfs(int u, int p) {
vis[u] = true;
for (int v: adj[u]) {
if (v == p)
continue;
dfs(v, u);
sp[u] ^= sp[v];
}
if (p != 0 && sp[u] == 0)
cout << u << " " << p << "\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int m;
cin >> n >> m;
for (int v = 1; v <= n; v++)
sef[v] = v;
for (int e = 0; e < m; e++) {
int u, v;
cin >> u >> v;
if (connect(u, v)) {
int f = rnd();
sp[u] ^= f;
sp[v] ^= f;
}
}
for (int v = 1; v <= n; v++) {
if (vis[v])
continue;
dfs(v, 0);
}
return 0;
}
