#include <bits/stdc++.h>
using namespace std;
using LL = long long;
const int mo = 1e9 + 7;
LL qpow(LL a, LL b) {
  LL ans = 1;
  a %= mo;
  while (b) {
    if (b & 1) ans = ans * a % mo;
    b >>= 1;
    a = a * a % mo;
  }
  return ans;
}
const int maxn = 3e5 + 5;
int what[maxn];
struct node {
  int a, b;
  bool operator<(const node& _) const {
    if (a != _.a) return a < _.a;
    return b < _.b;
  }
} a[maxn << 1];
bool flag[maxn];
map<pair<int, int>, bool> my;
int A[maxn], B[maxn], C[maxn];
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  int i, j;
  int cnt = 0;
  for (i = 0; i < m; i++) {
    scanf("%d%d", &a[cnt].a, &a[cnt].b);
    if (a[cnt].a > a[cnt].b) swap(a[cnt].a, a[cnt].b);
    my[{a[cnt].a, a[cnt].b}] = 1;
    cnt++;
    a[cnt] = {a[cnt - 1].b, a[cnt - 1].a};
    cnt++;
  }
  sort(a, a + cnt);
  memset(what, -1, sizeof(what));
  for (i = 0; i < cnt; i++) {
    if (a[i].a == 1) flag[a[i].b] = 1;
  }
  for (i = 1; i <= n; i++)
    if (!flag[i]) what[i] = 1;
  for (i = 1; i <= n; i++) {
    if (what[i] == -1) break;
  }
  if (i == n + 1) {
    printf("-1\n");
    exit(0);
  }
  int now = i;
  memset(flag, 0, sizeof(flag));
  for (i = 0; i < cnt; i++) {
    if (a[i].a == now) {
      flag[a[i].b] = 1;
    }
  }
  for (i = 1; i <= n; i++) {
    if (!flag[i]) {
      if (what[i] != -1) {
        printf("-1\n");
        exit(0);
      }
      what[i] = 2;
    }
  }
  LL num1 = 0, num2 = 0, num3 = 0;
  for (i = 1; i <= n; i++) {
    if (what[i] == 1) {
      A[num1++] = i;
    } else if (what[i] == 2) {
      B[num2++] = i;
    } else
      C[num3++] = i;
  }
  if (!num1 || !num2 || !num3) {
    printf("-1\n");
    exit(0);
  }
  if ((num1 - 1) * (num2 - 1) + (num1 - 1) * (num3 - 1) +
          (num2 - 1) * (num3 - 1) >
      m) {
    printf("-1\n");
    exit(0);
  }
  int ta, tb;
  for (i = 0; i < num1; i++) {
    for (j = 0; j < num2; j++) {
      ta = A[i], tb = B[j];
      if (ta > tb) swap(ta, tb);
      if (!my[{ta, tb}]) {
        printf("-1\n");
        exit(0);
      }
      my[{ta, tb}] = 0;
    }
  }
  for (i = 0; i < num1; i++) {
    for (j = 0; j < num3; j++) {
      ta = A[i], tb = C[j];
      if (ta > tb) swap(ta, tb);
      if (!my[{ta, tb}]) {
        printf("-1\n");
        exit(0);
      }
      my[{ta, tb}] = 0;
    }
  }
  for (i = 0; i < num2; i++) {
    for (j = 0; j < num3; j++) {
      ta = B[i], tb = C[j];
      if (ta > tb) swap(ta, tb);
      if (!my[{ta, tb}]) {
        printf("-1\n");
        exit(0);
      }
      my[{ta, tb}] = 0;
    }
  }
  for (const auto& x : my) {
    if (x.second == 1) {
      printf("-1\n");
      exit(0);
    }
  }
  for (i = 1; i < n; i++) {
    if (what[i] == -1)
      printf("3 ");
    else
      printf("%d ", what[i]);
  }
  if (what[i] == -1)
    printf("3 ");
  else
    printf("%d ", what[i]);
  return 0;
}
