#include <bits/stdc++.h>
#define int long long
#define ll long long
using ull = unsigned long long;
using namespace std;
const int INF = 1ll << 50;
const int MOD = 1e9 + 7;
#define dump(x)                             \
    if (dbg) {                              \
        cerr << #x << " = " << (x) << endl; \
    }
#define overload4(_1, _2, _3, _4, name, ...) name
#define FOR1(n) for (ll i = 0; i < (n); ++i)
#define FOR2(i, n) for (ll i = 0; i < (n); ++i)
#define FOR3(i, a, b) for (ll i = (a); i < (b); ++i)
#define FOR4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define FOR(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define FORR(i, a, b) for (int i = (a); i <= (b); ++i)
#define bit(n, k) ((n >> k) & 1) /*nのk bit目*/
template <class T>
bool chmin(T& a, const T& b) {
    if (a > b) {
        a = b;
        return 1;
    } else
        return 0;
}
template <class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return 1;
    } else
        return 0;
}
void Yes(bool flag = true) {
    if (flag)
        cout << "Yes" << endl;
    else
        cout << "No" << endl;
}
void No(bool flag = true) {
    Yes(!flag);
}
void YES(bool flag = true) {
    if (flag)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
}
void NO(bool flag = true) {
    YES(!flag);
}
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define SZ(x) ((int)(x).size())
#define vi vector<int>
//#define P pair<int, int>
//#define V vector<int>
//#define S set<int>
#define itn int
bool dbg = false;

int N, M;
vector<vector<pair<int, int>>> G;
vector<vector<pair<int, int>>> G2;
int vertex[101010];  //頂点
int node[101010];    //頂点
int A[101010], B[101010];

int cnt[101010];
int ans[101010];

void dfs1(int idx, int par) {
    vertex[idx] = 1;
    for (auto& nxt : G[idx]) {
        if (nxt.first == par)
            continue;
        if (!vertex[nxt.first]) {
            dfs1(nxt.first, idx);
            G2[idx].pb({nxt.first, nxt.second});
            node[nxt.second] = 1;
        }
    }
}

int dfs2(int idx, int par) {
    for (auto& nxt : G2[idx]) {
        if (nxt.first == par)
            continue;
        int tmp;
        if ((tmp = dfs2(nxt.first, idx)) % 2) {
            ans[nxt.second] = nxt.first;
        } else {
            ans[nxt.second] = idx;
            cnt[idx]++;
        }
    }
    return cnt[idx] % 2;
}

void solve() {
    G2.resize(N);
    if (M % 2) {
        cout << -1 << endl;
        return;
    }
    dfs1(0, -1);
    FOR(M) {
        if (!node[i]) {
            ans[i] = A[i];
            cnt[A[i]]++;
        }
    }
    dfs2(0, -1);
    FOR(M) {
        if (A[i] != ans[i]) {
            swap(A[i], B[i]);
        }
        cout << A[i] + 1 << " " << B[i] + 1 << endl;
    }
}

signed main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    cin >> N >> M;
    G.resize(N);
    FOR(M) {
        int a, b;
        cin >> a >> b;
        a--;
        b--;
        A[i] = a;
        B[i] = b;
        G[a].pb({b, i});
        G[b].pb({a, i});
    }

    solve();
    return 0;
}


Measured memory_bytes: 24832