#include <bits/stdc++.h>
using namespace std;
#define Rep(i,n) for(int i=0;i<(int)(n);i++)
#define For(i,n1,n2) for(int i=(int)(n1);i<(int)(n2);i++)
#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define RREP(i,n) for(ll i=((ll)(n)-1);i>=0;i--)
#define FOR(i,n1,n2) for(ll i=(ll)(n1);i<(ll)(n2);i++)
#define RFOR(i,n1,n2) for(ll i=((ll)(n1)-1);i>=(ll)(n2);i--)
#define all(a)  (a).begin(),(a).end()
#define SORT(a) sort((a).begin(),(a).end())
#define oorret 0
#define oor(x) [&](){try{x;} catch(const out_of_range& oor){return oorret;} return x;}()
#define IOS cin.tie(0),ios::sync_with_stdio(false)
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
template<typename T1, typename T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return 1; }return 0; }
template<typename T1, typename T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return 1; }return 0; }
template<class Type>struct is_vector : std::false_type {};
template<class ValueType, class Alloc>struct is_vector<std::vector<ValueType, Alloc>> : std::true_type {};
template <typename T> inline ostream& operator << (ostream& out, const vector<T>& v) {
	if (v.empty())return out;
	constexpr bool is_vector_v = is_vector<T>::value;
	if (is_vector_v)for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? "\n" : "");
	else for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? " " : "");
	return out;
}
inline void put() {}
template<class T> inline void put(const T& first) { std::cout << first << "\n"; }
template<class T, class... N> inline void put(const T& first, const N& ... rest) { std::cout << first << " "; put(rest...); }
inline void putn() {}
template<class T, class... N> inline void putn(const T& first, const N& ... rest) { std::cout << first << "\n"; putn(rest...); }

int cn = 0, n, m;
void dfs(vector<vector<int>>& path, vector<int>& tr, int v, vector<int>& cnt,vector<int>& u) {
	REP(i, path[v].size()) {
		int t = path[v][i];
		if (tr[t] < 0) {
			tr[t] = v;
			cnt[v]++;
			//u[cn] = 1;
			dfs(path, tr, t, cnt, u);
		}
		cn++;
	}
	return;
}
vector<P> eul;
vector<int> pos, neg;
void eular(vector<vector<int>>& path,vector<int>& tr,int v) {
	pos[v] = eul.size();
	eul.push_back(P(v,1));
	REP(i, path[v].size()) {
		int t = path[v][i];
		if (tr[t] == v) {
			eular(path, tr, t);
		}
	}
	neg[v] = eul.size();
	eul.push_back(P(v, -1));
}
vector<int> imos;
vector<P> ans;
void dfs2(vector<vector<int>>& path, vector<int>& tr, int v) {
	//eul.push_back(P(v, 1));
	REP(i, path[v].size()) {
		int t = path[v][i];
		if (tr[t] == v) {
			dfs2(path, tr, t);
		} else if(tr[v]!=t && v>t) {
			ans.push_back(P(v,t));
			imos[0]++;
			imos[neg[v]]--;
		}
	}
	//eul.push_back(P(v, -1));
}

int main() {
	IOS;
	cin >> n >> m;
	if (m % 2 == 1) {
		put(-1);
		return 0;
	}
	vector<int> a(m), b(m);
	vector<vector<int>> path(n);
	vector<int> u(m, 0);
;	REP(i, m) {
		cin >> a[i] >> b[i];
		a[i]--;
		b[i]--;
		path[a[i]].push_back(b[i]);
		path[b[i]].push_back(a[i]);
	}
	vector<int> tr(n, -1);
	vector<int> le(n, 1), cnt(n, 0);
	tr[0] = 0;
	dfs(path, tr, 0, cnt, u);
	tr[0] = -1;
	queue<int> q;
	vector<int> ent(n, 0), ou(n, 0), ang(n, -1);
	REP(i, n) {
		if (cnt[i]==0) {
			q.push(i);
		}
	}
	while (!q.empty()) {
		int p = q.front();
		q.pop();
		if (ou[p] % 2 == 0) {
			if (tr[p] >= 0) {
				ou[tr[p]]++;
				ang[p] = 1;
			}
		} else if(p > 0) {
			ou[p]++;
			ang[p] = 0;
		}
		if (tr[p] >= 0) {
			cnt[tr[p]]--;
			if (cnt[tr[p]] == 0) {
				q.push(tr[p]);
			}
		}
	}
	pos.resize(n,0);
	neg.resize(n,0);
	eular(path, tr, 0);
	imos.resize(eul.size());
	dfs2(path, tr, 0);
	vector<ll> s(imos.size() + 1);
	s[0] = 0;
	REP(i, imos.size()) {
		s[i + 1] = s[i] + imos[i];
	}
	REP(i, n - 1) {
		int ne = i + 1;
		ll st = s[pos[ne]+1] - s[neg[ne]+1];
		if (st % 2 == 0) {
			if (ang[ne] == 1) {
				ans.push_back(P(tr[ne], ne));
			} else {
				ans.push_back(P(ne, tr[ne]));
			}
		} else {
			if (ang[ne] == 0) {
				ans.push_back(P(tr[ne], ne));
			} else {
				ans.push_back(P(ne, tr[ne]));
			}
		}
	}
	REP(i, ans.size()) {
		cout << ans[i].first+1 << " " << ans[i].second+1 << endl;
	}
	return 0;
}


Measured memory_bytes: 29676