#include <bits/stdc++.h>
using namespace std;
#define int long long
#define stoi stoll
using pii=pair<int,int>;
using vi = vector<int>;
using vvi = vector<vi>;
#define all(c) begin(c),end(c)
#define rall(c) rbegin(c),rend(c)
#define fore(x,c) for(auto &&x:c)
#define rep(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define rrep(i, a, n) for(int i=(int)(n-1);i>=a;--i)
#define sz(c) ((int)c.size())
#define contains(c,x) (c.find(x)!=end(c))
#define inseg(l,x,r) ((l)<=(x)&&(x)<(r))
#define dump(...)
#define pb push_back
#define _ 0
const signed INF_=1001001001; const long long INF=1001001001001001001LL;
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) os<<*i<<(i==end(v)-1?"":" ");return os;}
template<class T> istream& operator>>(istream &is,vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) is>>*i;return is;}
template<class T,class U> istream& operator>>(istream &is, pair<T,U> &p) {
    is>>p.first>>p.second;return is;}
template<class T, class U> bool chmax(T &a,const U &b){return a<b?a=b,1:0;}
template<class T, class U> bool chmin(T &a,const U &b){return a>b?a=b,1:0;}
template <class T> void psum(T& c) {partial_sum(begin(c), end(c), begin(c));}
template<class T> using heap=priority_queue<T,vector<T>,greater<T>>;
struct before_main_function {
    before_main_function() {
        cin.tie(nullptr); ios::sync_with_stdio(0);
        cout << setprecision(15) << fixed;
        // #define endl "\n"
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

signed main() {
    int N, M;
    cin >> N >> M;
    vvi G(N);
    vi deg(N);
    rep(i, 0, M) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        G[a].push_back(b);
        G[b].push_back(a);
        deg[a]++;
        deg[b]++;
    }
    
    if (M % 2) {
        cout << -1 << endl;
        return 0;
    }

    vector<pii> ans;
    vector<bool> vis(N);
    vector<int> out(N);
    set<pii> removed;

    set<pii> vs;
    
    auto dfs = [&](auto fun, int v) -> void {
        if (sz(G[v]) == 1) {
            ans.push_back({G[v][0], v});
            removed.insert({G[v][0], v});
            removed.insert({v, G[v][0]});
            out[G[v][0]]++;
            deg[v]--;
            deg[G[v][0]]--;
        }

        vis[v] = true;
        for (int w : G[v]) {
            if (vis[w]) continue;
            fun(fun, w);
        }
    };
    dfs(dfs, 0);

    rep(i, 0, N) {
        if (sz(G[i]) != 1) {
            vs.insert({deg[i], i});
        }
    }

    while (sz(vs)) {
        int d, v;
        tie(d, v) = *vs.begin();
        assert(d == deg[v]);
        vs.erase(vs.begin());
        for (int w : G[v]) {
            if (removed.count({v, w})) {
                continue;
            }
            if (out[v] % 2 == 0 && deg[v] % 2 == 1) {
                d--;
                ans.push_back({w, v});
                out[w]++;
            } else {
                ans.push_back({v, w});
                out[v]++;
            }
            removed.insert({v, w});
            removed.insert({w, v});
            vs.erase({deg[w], w});
            deg[w]--;
            vs.insert({deg[w], w});
            deg[v]--;
        }
    }

    rep(i, 0, sz(ans)) {
        cout << ans[i].first + 1 << " " << ans[i].second + 1 << endl;
    }
    return (0^_^0);
}



Measured memory_bytes: 29552