вершинная двусвязность

/*
ЗАПУСКАЕМ
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*/
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma,sse4")
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,unswitch-loops,fast-math")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include <iostream>
#include <string>
#include <sstream>
#include <cmath>
#include <memory.h>
#include <algorithm>
#include <stack>
#include <deque>
#include <iomanip>
#include <stdio.h>
#include <queue>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <ctime>
#include <cstdlib>
#include <cassert>
#include <iterator>
#include <chrono>
#include <array>
#include <bitset>
//#define int long long
#define itn long long
#define fro for
#define intt __int128
#define pii pair <int, int>
#define debug(x) cerr << (#x) << " " << (x) << endl
#define pb push_back
#define all(vc) vc.begin(), vc.end()
#define fir first
#define sec second
#define endl "\n"
#define un unsigned
#define INF 1000000010
#define EPS 0.0000000001
#define double long double
using namespace std;

const int N = 200005, R = 1 << 20, MOD = 1e9 + 7, ABC = 26, logn = 20;
const int BUBEN = 1001;
const double PI = acos(-1);

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

map<pii, int> num;
map<pii, int> mp;
int up[N], d[N];
vector<bool> used(N);
bool art_point[N];

void dfs(vector<vector<int>>& gr, int v, int p = -1) {
    used[v] = 1;
    if (p != -1)
        d[v] = d[p] + 1;
    else
        d[v] = 1;
    up[v] = d[v];
    int cnt = 0;
    for (int i : gr[v]) {
        if (!used[i]) {
            cnt++;
            dfs(gr, i, v);
            up[v] = min(up[i], up[v]);
            if (up[i] >= d[v] && p != -1) {
                art_point[v] = 1;
            }
        }
        else if (i != v) {
            up[v] = min(up[v], d[i]);
        }
    }
    if (p == -1 && cnt > 1)
        art_point[v] = 1;
}

int color[N];
int mxcolor = 0;
map<pii, int>suka;
void dfs2(vector<vector<int>>& gr, int v, int p, int cur) {
    used[v] = 1;
    for (int u : gr[v]) {
        if (p == u)
            continue;

        if (!used[u]) {
            if (art_point[v] && up[u] >= d[v]) {
                mxcolor++;
                suka[{u, v}] = mxcolor;
                suka[{v, u}] = mxcolor;
                dfs2(gr, u, v, mxcolor);
            }
            else {
                suka[{u, v}] = cur;
                suka[{v,u}] = cur;
                dfs2(gr, u, v, cur);
            }
        }
        if (d[u] < d[v]) {
            suka[{u, v}] = cur;
            suka[{v, u}] = cur;
        }
    }
}

bool cmp(set<int>& a, set<int>& b) {
    if (a.size() > 0)
        if (b.size() > 0)
            return *a.begin() < *b.begin();
        else
            return 1;
    else
        return 0;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    srand(time(0));
    cout.precision(17);

    int n, m;
    cin >> n >> m;

    vector<vector<int>> gr(n + 1);
    vector<pii> kok(m + 1);
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        gr[a].push_back(b);
        gr[b].push_back(a);
        mp[{a, b}]++;
        mp[{b, a}]++;
        num[{a, b}] = i + 1;
        num[{b, a}] = i + 1;
        kok[i+1] = { a, b };
    }

    fro(int i = 1; i <= n; i++)
        if (!used[i])
            dfs(gr, i, i);
    used.assign(n + 1, 0);
    for (int i = 1; i <= n; i++)
        if (!used[i]) {
            mxcolor++;
            dfs2(gr, i, -1, mxcolor);
        }
    vector<set<int>> lol(n + 1);
    for (int i = 1; i <= m; i++) {
        lol[suka[kok[i]]].insert(i);
    }
    sort(all(lol), cmp);
    int cntt = 0;
    for (int i = 0; i < lol.size(); i++)
        if (lol[i].size() > 0)
            cntt++;
    for (int i = 0; i <= n; i++)
        for (int j : lol[i])
            color[j] = i + 1;
    cout << cntt << endl;
    for (int i = 1; i <= m; i++)
        cout << color[i] << " ";
    return 0;
}
/*
5 5
1 2
1 2
2 3
3 4
3 4
*/