#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  scanf("%d", &t);
  while (t--) {
    int n, m;
    scanf("%d %d", &n, &m);
    vector<vector<int> > g(n);
    while (m--) {
      int x, y;
      scanf("%d %d", &x, &y);
      x--, y--;
      g[x].push_back(y);
      g[y].push_back(x);
    }
    bool ok = true;
    for (int i = 0; i < n; i++)
      if (g[i].size() % 2 != 0) {
        ok = false;
        break;
      }
    if (ok) {
      printf("1\n");
      for (int i = 0; i < n; i++) {
        if (i > 0) printf(" ");
        printf("1");
      }
      printf("\n");
      continue;
    }
    vector<bitset<2001> > v(n);
    for (int i = 0; i < n; i++) {
      if (g[i].size() % 2 == 0) {
        for (int j : g[i]) v[i].set(j);
      } else {
        for (int j : g[i]) v[i].set(j);
        v[i].set(i);
        v[i].set(n);
      }
    }
    int k = 0;
    vector<int> var(n, -1), label(n, 0);
    for (int i = 0; i < n; i++) {
      bool found = false;
      for (int j = k; j < n; j++)
        if (v[j].test(i)) {
          swap(v[k], v[j]);
          found = true;
          break;
        }
      if (!found) continue;
      for (int j = k + 1; j < n; j++)
        if (v[j].test(i)) {
          v[j] ^= v[k];
        }
      var[k] = i;
      k++;
    }
    int l = n - 1;
    for (int i = k - 1; i >= 0; i--) {
      while (l > var[i]) {
        label[l] = 0;
        l--;
      }
      label[l] = v[i].test(n);
      for (int j = i - 1; j >= 0; j--)
        if (v[j].test(l)) v[j] ^= v[i];
      l--;
    }
    printf("2\n");
    for (int i = 0; i < n; i++) {
      if (i > 0) printf(" ");
      printf("%d", label[i] + 1);
    }
    printf("\n");
  }
  return 0;
}
