#include <bits/stdc++.h>
using namespace std;
template <typename T>
void maxtt(T& t1, T t2) {
  t1 = max(t1, t2);
}
template <typename T>
void mintt(T& t1, T t2) {
  t1 = min(t1, t2);
}
bool debug = 0;
int n, m, k;
int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0};
string direc = "RDLU";
long long ln, lk, lm;
void etp(bool f = 0) {
  puts(f ? "YES" : "NO");
  exit(0);
}
void addmod(int& x, int y, int mod = 998244353) {
  assert(y >= 0);
  x += y;
  if (x >= mod) x -= mod;
  assert(x >= 0 && x < mod);
}
void et(int x = -1) {
  printf("%d\n", x);
  exit(0);
}
long long fastPow(long long x, long long y, int mod = 998244353) {
  long long ans = 1;
  while (y > 0) {
    if (y & 1) ans = (x * ans) % mod;
    x = x * x % mod;
    y >>= 1;
  }
  return ans;
}
long long gcd1(long long x, long long y) { return y ? gcd1(y, x % y) : x; }
bitset<2005> a[2005];
int dg[2005], ans[2005];
void gauss() {
  for (int(i) = 1; (i) <= (int)(n); (i)++) {
    int j = i;
    while (j <= n && a[j][i] == 0) j++;
    if (j > n) continue;
    if (i != j) {
      swap(a[i], a[j]);
    }
    for (int j = 1; j <= n; j++)
      if (i != j) {
        if (a[j][i] == 1) {
          a[j] ^= a[i];
        }
      }
  }
  for (int i = n; i; i--) {
    ans[i] = a[i][n + 1];
    for (int j = i + 1; j <= n; j++)
      if (a[i][j]) ans[i] ^= ans[j];
  }
}
void fmain(int tid) {
  scanf("%d%d", &n, &m);
  for (int(i) = 1; (i) <= (int)(n); (i)++) {
    dg[i] = 0;
    a[i].reset();
    ans[i] = 0;
  }
  for (int(i) = 1; (i) <= (int)(m); (i)++) {
    int u, v;
    scanf("%d%d", &u, &v);
    dg[u]++;
    dg[v]++;
    a[u][v] = 1;
    a[v][u] = 1;
  }
  bool fg = 1;
  for (int(i) = 1; (i) <= (int)(n); (i)++)
    if (dg[i] & 1) fg = 0;
  if (fg) {
    puts("1");
    for (int(i) = 1; (i) <= (int)(n); (i)++) printf("1 ");
    puts("");
    return;
  }
  puts("2");
  for (int(i) = 1; (i) <= (int)(n); (i)++)
    if (dg[i] & 1) {
      a[i][i] = 1;
      a[i][n + 1] = 1;
    }
  gauss();
  for (int(i) = 1; (i) <= (int)(n); (i)++) printf("%d ", ans[i] + 1);
  puts("");
}
int main() {
  int t = 1;
  scanf("%d", &t);
  for (int(i) = 1; (i) <= (int)(t); (i)++) {
    fmain(i);
  }
  return 0;
}
