7 20
4 6
6 7
4 5
1 2
2 4
1 7
3 5
2 1
6 2
6 1
7 3
3 2
3 6
3 1
3 4
2 5
1 6
7 4
6 3
7 5
 8 23
1 2
1 4
1 6
1 8
2 3
2 4
2 5
2 6
2 7
2 8
3 4
3 5
3 6
3 7
3 8
4 5
4 6
4 7
5 6
5 7
5 8
6 8
7 8
 4 4
2 1
3 1
1 4
3 2
 8 18
1 4
1 6
1 7
2 3
2 4
2 5
2 6
2 7
2 8
3 4
3 8
4 7
5 6
5 7
5 8
6 7
6 8
7 8
 10 34
7 10
2 3
2 4
2 5
9 10
2 7
2 8
2 10
4 5
4 6
4 7
4 8
4 9
6 7
6 8
6 9
6 10
1 2
1 3
1 5
8 9
1 6
1 7
1 8
1 9
1 10
3 4
3 5
3 6
3 8
3 10
5 6
5 9
5 10
 5 7
1 2
2 3
3 4
1 5
2 5
3 5
4 5
 2 0
 8 23
2 7
7 5
8 6
8 2
6 3
3 5
8 1
8 4
8 3
3 4
1 2
2 6
5 2
6 4
7 6
6 5
7 8
7 1
5 4
3 7
1 4
3 1
3 2
 2 1
1 2
 6 9
1 2
1 4
1 5
2 3
2 5
2 6
3 5
4 6
5 6
 12 56
9 5
2 6
9 8
5 4
1 11
1 6
4 1
1 10
10 3
8 4
5 1
9 1
5 10
2 7
11 5
6 11
5 8
7 6
3 2
12 7
8 6
12 3
1 2
8 1
2 11
10 12
4 6
5 12
2 4
10 2
7 3
12 11
7 10
7 1
9 2
11 9
9 10
8 7
11 3
7 9
5 7
4 12
3 5
12 2
4 10
9 12
5 2
9 4
11 8
8 2
3 6
4 11
8 10
6 10
3 9
3 4
 12 58
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 10
1 11
1 12
2 3
2 4
2 5
2 6
2 7
2 8
2 9
2 10
2 11
2 12
3 4
3 5
3 6
3 7
3 8
3 9
3 10
3 11
3 12
4 5
4 6
4 8
4 11
4 12
5 6
5 7
5 8
5 9
5 10
5 11
6 7
6 8
6 9
6 10
6 11
6 12
7 8
7 9
7 10
7 11
7 12
8 9
8 10
8 11
9 10
9 11
9 12
10 12
 4 3
2 1
3 1
4 2
 3 1
2 3
 6 10
1 2
1 3
1 4
1 6
2 3
2 4
2 5
3 5
3 6
4 6
 11 49
10 3
6 4
11 3
7 6
10 6
6 1
4 3
10 2
4 5
9 2
10 1
5 7
1 5
9 7
2 11
8 6
3 9
2 5
9 5
6 5
1 4
11 9
1 7
8 10
3 6
3 7
11 5
6 9
4 10
8 7
4 9
8 2
4 2
8 11
7 4
9 10
8 1
10 7
3 2
5 8
8 9
1 3
2 7
10 11
5 3
10 5
4 11
1 11
8 3
 5 4
1 4
2 3
4 3
4 2
 4 3
1 2
3 1
4 3
 4 3
1 3
1 4
2 3
 10 36
7 8
7 9
2 3
2 4
2 5
9 10
2 7
2 8
2 9
2 10
4 5
4 6
4 7
4 8
4 10
6 7
6 9
6 10
1 2
1 3
1 4
8 9
1 5
8 10
1 7
1 8
1 9
1 10
3 4
3 6
3 7
3 9
5 6
5 7
5 9
5 10
 8 15
2 1
4 5
2 4
3 4
2 5
3 5
2 6
3 6
5 6
4 6
2 7
3 8
2 8
3 7
6 7

3
1 2 4 
 3
1 2 5 
 2
1 3 
 1
8 
 1
10 
 2
1 4 
 1
2 
 3
1 3 4 
 2
1 1 
 1
6 
 3
1 4 7 
 4
1 1 1 9 
 1
4 
 1
3 
 1
6 
 5
1 1 1 2 6 
 1
5 
 1
4 
 1
4 
 2
2 8 
 1
8 

#include <bits/stdc++.h>
using namespace std;
set<int> bag[200005 * 5];
int id[200005 * 5];
int P[200005 * 6];
int n, q;
vector<int> E[200005];
int MaxId = 0;
int Cnt[200005 * 6];
int f(int u) {
  if (P[u] != u) return P[u] = f(P[u]);
  return u;
}
void build(int p, int s, int e) {
  id[p] = p;
  MaxId = max(MaxId, p);
  if (s == e) return;
  int m = (s + e) / 2;
  build(p * 2 + 1, s, m);
  build(p * 2 + 2, m + 1, e);
}
void upd(int p, int s, int e, int l, int r, int i) {
  if (s > r || e < l) return;
  if (l <= s && e <= r) {
    bag[p].insert(i);
    return;
  }
  int m = (s + e) / 2;
  upd(p * 2 + 1, s, m, l, r, i);
  upd(p * 2 + 2, m + 1, e, l, r, i);
}
void addE(int u, int v) { P[f(u)] = f(v); }
void dnc(int p, int s, int e) {
  for (auto it : bag[p]) {
    addE(it + MaxId, p);
  }
  for (int i = s; i <= e && bag[p].size(); i++) {
    addE(p, i + MaxId);
  }
  if (s == e) {
    return;
  }
  int m = (s + e) / 2;
  dnc(p * 2 + 1, s, m);
  dnc(p * 2 + 2, m + 1, e);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> q;
  for (int i = 0; i < q; i++) {
    int u, v;
    cin >> u >> v;
    if (u > v) swap(u, v);
    E[u].push_back(v);
  }
  build(0, 1, n);
  for (int i = 0; i <= MaxId + n; i++) P[i] = i;
  for (int i = 1; i <= n; i++) {
    int last = i;
    int pos = lower_bound(E[i].begin(), E[i].end(), last) - E[i].begin();
    while (true) {
      if (pos == E[i].size()) break;
      int L = last + 1, R = E[i][pos];
      if (L < R) upd(0, 1, n, L, R - 1, i);
      last = R;
      pos++;
    }
    int L = last + 1, R = n;
    if (L <= R) {
      upd(0, 1, n, L, R, i);
    }
  }
  dnc(0, 1, n);
  for (int i = MaxId + 1; i <= MaxId + n; i++) {
    Cnt[f(i)]++;
  }
  vector<int> son;
  for (int i = 0; i <= MaxId + n; i++) {
    if (Cnt[f(i)] > 0) {
      son.push_back(Cnt[f(i)]);
      Cnt[f(i)] = 0;
    }
  }
  sort(son.begin(), son.end());
  cout << son.size() << endl;
  for (int i = 0; i < son.size(); i++) {
    if (i) cout << " ";
    cout << son[i];
  }
  cout << endl;
  return 0;
}
