#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <set>

using namespace std;

int MAXN = 200001;
int n, m;
int cur_color = 1;
int t;
vector<vector<pair<int, int>>> g(MAXN);
vector<bool> used(MAXN);
vector<int> ans;
vector<int> color(MAXN);
vector<int> tin(MAXN);
vector<int> up(MAXN);

void fillgraph();

void points_search();

void dfs_points(int v, int p);

void fillgraph() {
    t = 0;
    cin >> n >> m;
    for (int i = 0; i < n; i++) {
        used[i] = false;
    }
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        a--;
        b--;
//        if (a > b) {
//            std::swap(a, b);
//        }
        bool flag = false;
//        for (int j = 0; j < g[a].size(); j++) {
//            if (g[a][j] == b) {
//                flag = true;
//            }
//        }
//        for (int j = 0; j < g[b].size(); j++) {
//            if (g[b][j] == a) {
//                flag = true;
//            }
//        }
        if (!flag) {
            g[b].emplace_back(a, i);
            g[a].emplace_back(b, i);
        }
    }
}

void points_search() {
    for (int i = 0; i < n; i++) {
        if (!used[i]) {
            dfs_points(i, -1);
        }
    }
}

void dfs_points(int v, int p) {
    used[v] = true;
    tin[v] = t;
    up[v] = t;
    t++;
    int ch = 0;
    for (int i = 0; i < g[v].size(); i++) {
        int to = g[v][i].first;
        if (to != p) {
            if (!used[to]) {
                dfs_points(to, v);
                up[v] = min(up[v], up[to]);
                if (up[to] >= tin[v]) {
                    if (p >= 0) {
                        ans.push_back(v);
                    }
                    ch++;
                }
            } else {
                up[v] = min(up[v], tin[to]);
            }
        }
    }
    if (p == -1) {
        if (ch > 1) {
            ans.push_back(v);
        }
    }
}

void vert(int v, int col, int p) {
    {
        int i = v;
        used[v] = true;
        for (int j = 0; j < g[i].size(); j++) {
            int to = g[v][j].first;
            if (p != to) {
                if (used[to] == false) {
                    if (tin[v] <= up[to]) {
                        int cur = ++cur_color;
                        color[g[v][j].second] = cur;
                        vert(to, cur, v);
                    } else {
                        color[g[v][j].second] = col;
                        vert(to, col, v);
                    }
                } else if (tin[v] > tin[to]) {
                    color[g[v][j].second] = col;
                }
            }
        }
    }
}

void comp_vert() {
    for (int i = 0; i < n; i++) {
        if (used[i] == false) {
            cur_color++;
            vert(i, cur_color, -1);
        }
    }
}

int main() {
    fillgraph();
    for (int i = 0; i < n; i++) {
        used[i] = false;
    }
    points_search();
    for (int i = 0; i < n; i++) {
        used[i] = false;
    }
    comp_vert();
    set<int> different;
    for (int i = 0; i < m; i++) {
        different.insert(color[i]);
    }
    cout << different.size() << '\n';
    vector<int> answer;
    map<int, int> colorMap;
    int index = 1;
    for (auto el : different) {
        colorMap[el] = index;
        index++;
    }
    for (int i = 0; i < m; i++) {
        answer.push_back((*colorMap.find(color[i])).second);
    }
    for (int i = 0; i < answer.size(); i++) {
        cout << answer[i] << " ";
    }
    cout << '\n';
    return 0;
}