//#define NDEBUG
#include <cstddef>
#include <cstdint>
#include <vector>

namespace n91 {

using i8 = std::int_fast8_t;
using i32 = std::int_fast32_t;
using i64 = std::int_fast64_t;
using u8 = std::uint_fast8_t;
using u32 = std::uint_fast32_t;
using u64 = std::uint_fast64_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

constexpr usize operator"" _z(unsigned long long x) noexcept {
  return static_cast<usize>(x);
}

class rep {
  const usize f, l;

public:
  class itr {
    friend rep;
    usize i;
    constexpr itr(const usize x) noexcept : i(x) {}

  public:
    void operator++() noexcept { ++i; }
    constexpr usize operator*() const noexcept { return i; }
    constexpr bool operator!=(const itr x) const noexcept { return i != x.i; }
  };
  constexpr rep(const usize first, const usize last) noexcept
      : f(first), l(last) {}
  constexpr itr begin() const noexcept { return itr(f); }
  constexpr itr end() const noexcept { return itr(l); }
};
class revrep {
  const usize f, l;

public:
  class itr {
    friend revrep;
    usize i;
    constexpr itr(usize x) noexcept : i(x) {}

  public:
    void operator++() noexcept { --i; }
    constexpr usize operator*() const noexcept { return i; }
    constexpr bool operator!=(const itr x) const noexcept { return i != x.i; }
  };
  constexpr revrep(usize first, usize last) noexcept : f(--first), l(--last) {}
  constexpr itr begin() const noexcept { return itr(l); }
  constexpr itr end() const noexcept { return itr(f); }
};
template <class T> using vec_alias = std::vector<T>;
template <class T> auto md_vec(const usize n, const T &value) {
  return std::vector<T>(n, value);
}
template <class... Args> auto md_vec(const usize n, Args... args) {
  return std::vector<decltype(md_vec(args...))>(n, md_vec(args...));
}
template <class T> constexpr T difference(const T &a, const T &b) {
  return a < b ? b - a : a - b;
}

} // namespace n91

#include <algorithm>
#include <iostream>
#include <set>
#include <utility>

namespace n91 {

void main_() {
  usize n, m;
  std::cin >> n >> m;

  if (m % 2_z != 0_z) {
    std::cout << "-1" << std::endl;
    return;
  }

  struct edge {
    usize to;
    bool f;
  };
  auto g = md_vec(n, 0_z, edge());

  std::vector<bool> par(n), r(n);

  for (const auto i : rep(0_z, m)) {
    usize a, b;
    std::cin >> a >> b;
    --a;
    --b;
    g[a].push_back({b, true});
    g[b].push_back({a, false});
    par[a].flip();
  }

  std::set<std::pair<usize, usize>> flip_edge;

  const auto dfs = [&](const auto &dfs, const usize v) -> bool {
    r[v] = true;
    bool f = false;

    for (const auto &e : g[v]) {
      if (r[e.to]) {
        continue;
      }
      if (dfs(dfs, e.to)) {
        flip_edge.emplace(v, e.to);
        f = !f;
      }
    }

    return f != par[v];
  };
  dfs(dfs, 0_z);

  for (const auto i : rep(0_z, n)) {
    for (const auto &e : g[i]) {
      if (e.f) {
        if (flip_edge.count({i, e.to}) || flip_edge.count({e.to, i})) {
          std::cout << e.to + 1_z << " " << i + 1_z << std::endl;
        } else {
          std::cout << i + 1_z << " " << e.to + 1_z << std::endl;
        }
      }
    }
  }
}

} // namespace n91

int main() {
  n91::main_();
  return 0;
}


Measured memory_bytes: 14720