#include <iostream>
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <vector>

using namespace std;

const int mx = 200001;
bool color[mx];
int N, M, timer, in[mx], up[mx], count, head, clr[mx], maxcolor;
vector<int> rebr[mx];
vector<int> rebr_number[mx];
vector<int> stash;

void dfs(int v, int p)
    {
        color[v] = true;
        timer++;
        in[v] = timer - 1;
        up[v] = timer - 1;
        for (int i = 0; i < rebr[v].size(); i++)
            {
                if (clr[rebr_number[v][i]] == 0)
                    stash.push_back(rebr_number[v][i]);
                int to = rebr[v][i];
                if (to == p)
                    continue;
                if (color[to])
                    {
                        if (up[v] > in[to])
                            up[v] = in[to];
                    }
                else
                    {
                        if (v == head)
                            count++;
                        dfs(to, v);
                        up[v] = min(up[v], up[to]);
                        if (up[to] >= in[v])
                            {
                                maxcolor++;
                                int temp = 0;
                                while ( (stash.back() != rebr_number[v][i]) || (temp < 1) )
                                    {
                                        if (stash.back() == rebr_number[v][i])
                                            temp++;
                                        clr[stash.back()] = maxcolor;
                                        stash.pop_back();
                                    }
                                clr[rebr_number[v][i]] = maxcolor;
                                stash.pop_back();
                            }
                        else if (up[to] < up[v])
                            up[v] = up[to];
                    }
            }
    }

int main()
    {
        freopen("biconv.in","r",stdin);
        freopen("biconv.out","w",stdout);
        int M;
        scanf("%d %d\n", &N, &M);
        for(int i = 0; i < mx; i++)
            {
                color[i] = false;
                clr[i] = 0;
            }
        for(int i = 0; i < M; i++)
            {
                int a, b;
                scanf("%d %d\n", &a, &b);
                rebr[a].push_back( b);
                rebr[b].push_back( a);
                rebr_number[a].push_back(i + 1);
                rebr_number[b].push_back(i + 1);
            }
        maxcolor = 0;
        for(int i = 1; i <= N; i++)
            {
                timer = 0;
                head = i;
                count = 0;
                if (!color[i])
                    dfs(i, -1);
            }
        printf("%d\n", maxcolor);
        for(int i = 1; i <= M; i++)
            printf("%d ", clr[i]);
        fclose(stdin);
        fclose(stdout);
        return 0;
    }