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

// macros
#define pb emplace_back
#define mk make_pair
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define bit(n) (1LL<<(n))
// functions
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << p.first << " " << p.second; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
//  types
using ll = long long int;
using P = pair<int, int>;
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1000000007;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};
// io
struct fast_io{
  fast_io(){ios_base::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(20);}
} fast_io_;

vector<int> edges[100010], child[100010];
bool vis[100010];
set<P> st;
int U[100010], V[100010], to[100010], deg[100010];
int par[100010];
map<P, int> mp;

void dfs(int i){
  vis[i] = true;
  for(auto e: edges[i]){
    if(!vis[e]){
      child[i].pb(e);
      par[e] = i;
      st.insert(mk(min(i, e), max(i, e)));
      dfs(e);
    }
  }
}

void calc(int i){
  for(auto e: child[i]){
    calc(e);
  }
  if(i > 0){
    int idx = mp[mk(i, par[i])];
    if(deg[i] & 1){
      to[idx] = par[i];
      deg[i]++;
    }else{
      to[idx] = i;
      deg[par[i]]++;
    }
  }
}

int main(int argc, char const* argv[])
{
  int n, m;
  cin >> n >> m;
  rep(i, m){
    int u, v;
    cin >> u >> v, u--, v--;
    U[i] = u, V[i] = v;
    edges[u].pb(v);
    edges[v].pb(u);
  }
  if(m & 1){
    cout << -1 << endl;
    return 0;
  }
  dfs(0);
  rep(i, m){
    if(st.find(mk(min(U[i], V[i]), max(U[i], V[i]))) == st.end()){
      to[i] = U[i];
      deg[V[i]]++;
    }else{
      mp[mk(U[i], V[i])] = mp[mk(V[i], U[i])] = i;
    }
  }
  calc(0);
  rep(i, m){
    if(U[i] == to[i])cout << V[i] + 1 << " " << U[i] + 1 << endl;
    else cout << U[i] + 1 << " " << V[i] + 1 << endl;
  }
  return 0;
}


Measured memory_bytes: 40960