#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline bool upmin(T &x, T y) {
  return y < x ? x = y, 1 : 0;
}
template <typename T>
inline bool upmax(T &x, T y) {
  return x < y ? x = y, 1 : 0;
}
const long double eps = 1e-9;
const long double pi = acos(-1);
const int oo = 1 << 30;
const long long loo = 1ll << 60;
const int mods = 1e9 + 7;
const int inv2 = (mods + 1) >> 1;
const int MAXN = 100005;
const int INF = 0x3f3f3f3f;
namespace FastIO {
constexpr int SIZE = (1 << 21) + 1;
int num = 0, f;
char ibuf[SIZE], obuf[SIZE], que[65], *iS, *iT, *oS = obuf,
                                                *oT = obuf + SIZE - 1, c;
inline void flush() {
  fwrite(obuf, 1, oS - obuf, stdout);
  oS = obuf;
}
inline void putc(char c) {
  *oS++ = c;
  if (oS == oT) flush();
}
inline void getc(char &c) {
  for (c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++);
       !isalpha(c) && c != EOF;
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    ;
}
inline void reads(char *st) {
  char c;
  int n = 0;
  getc(st[++n]);
  for (c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++);
       isalpha(c);
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    st[++n] = c;
  st[n + 1] = '\0';
}
template <class I>
inline void read(I &x) {
  for (f = 1, c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                              (iS == iT ? EOF : *iS++))
                            : *iS++);
       c < '0' || c > '9';
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    if (c == '-') f = -1;
  for (x = 0; c >= '0' && c <= '9';
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    x = (x << 3) + (x << 1) + (c & 15);
  x *= f;
}
template <class I>
inline void print(I x) {
  if (x < 0) putc('-'), x = -x;
  if (!x) putc('0');
  while (x) que[++num] = x % 10 + 48, x /= 10;
  while (num) putc(que[num--]);
}
struct Flusher_ {
  ~Flusher_() { flush(); }
} io_Flusher_;
}  // namespace FastIO
using FastIO ::print;
using FastIO ::putc;
using FastIO ::read;
using FastIO ::reads;
vector<int> e[2005];
bitset<2005> A[2005];
void solve(int n) {
  for (int i = 0; i < n; ++i) {
    int id = i;
    for (int j = i; j < n; ++j)
      if (A[j][i]) {
        id = j;
        break;
      }
    if (id != i) swap(A[id], A[i]);
    for (int j = 0; j < n; ++j)
      if (i != j && A[j][i]) A[j] ^= A[i];
  }
}
signed main() {
  int Case;
  read(Case);
  while (Case--) {
    int n, m;
    read(n), read(m);
    for (int i = 1; i <= n; ++i) e[i].clear();
    for (int i = 1, u, v; i <= m; ++i)
      read(u), read(v), e[u].push_back(v), e[v].push_back(u);
    int flag = 0;
    for (int i = 1; i <= n; ++i) flag |= (e[i].size() & 1);
    if (!flag) {
      print(1), putc('\n');
      for (int i = 1; i <= n; ++i) print(1), putc(' ');
      putc('\n');
      continue;
    }
    print(2), putc('\n');
    for (int i = 0; i < n; ++i)
      for (int j = 0; j <= n; ++j) A[i][j] = 0;
    for (int i = 1; i <= n; ++i) {
      A[i - 1][n] = (e[i].size() & 1);
      for (auto v : e[i])
        A[i - 1][i - 1] = A[i - 1][i - 1] ^ 1,
                     A[i - 1][v - 1] = A[i - 1][v - 1] ^ 1;
    }
    solve(n);
    for (int i = 0; i < n; ++i) print(A[i][n] + 1), putc(' ');
    putc('\n');
  }
  return 0;
}
