#include <bits/stdc++.h>
using namespace std;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
const int INF = INT_MAX;
const long long INFLL = (long long)1e18;
const double PI = acos(-1.0);
template <class T>
T gcd(T a, T b) {
  return b ? gcd(b, a % b) : a;
}
template <class T>
T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
const int N = (int)1e5 + 5;
const int P = 1 << 18;
int n, m;
vector<pair<int, int> > a[105];
int G[105][105];
int main() {
  ios::sync_with_stdio(false);
  cout.setf(ios::fixed | ios::showpoint);
  cout.precision(8);
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    G[x][y] = G[y][x] = 1;
  }
  for (int i = 1; i <= n; i++) {
    a[i].push_back(make_pair(i, i));
  }
  int col = n + 1;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      if (G[i][j] == 1) {
        a[i].push_back(make_pair(col, i));
        a[j].push_back(make_pair(col, j));
        col++;
        G[i][j] = G[j][i] = 0;
      }
    }
  }
  for (int i = 1; i <= n; i++) {
    cout << (int)a[i].size() << endl;
    for (auto j : a[i]) {
      cout << j.first << ' ' << j.second << '\n';
    }
  }
  return 0;
}
