#include <iostream>
#include <vector>
#include <fstream>
#include <algorithm>
#include <stack>

using namespace std;

vector<int> used;
vector< vector< pair < int, int > > > g;

int timer;
int maxColour = -1;
vector<int> tin;
vector<int> up;

vector<int> colours;



void push(int v, int colour, int parent) {

	used[v] = 1;

	for (size_t i = 0; i < g[v].size(); ++i) {
		int to = g[v][i].first;
		int num = g[v][i].second;

		if (to == parent)
			continue;

		if (!used[to]) {
			if (up[to] >= tin[v]) {
				int t = ++maxColour;
				colours[num] = t;
				push(to, t, v);

			}
			else {
				colours[num] = colour;
				push(to, colour, v);
			}

		}
		else if (tin[to] < tin[v])
			colours[num] = colour;
	}

}



int dfs(int v, int parent) {

	used[v] = 1;
	tin[v] = up[v] = timer++;

	for (size_t i = 0; i < g[v].size(); ++i) {
		int to = g[v][i].first;

		if (to == parent)
			continue;

		if (used[to])
			up[v] = min(up[v], tin[to]);

		else {

			dfs(to, v);
			up[v] = min(up[v], up[to]);

		}
	}

	return 0;
}

int doSomething() {

	for (size_t v = 0; v < g.size(); ++v) {
		dfs(v, -1);
	}

	used.assign(used.size(), 0);
	maxColour = 0;
	for (size_t v = 0; v < g.size(); ++v) {
		if (!used[v]) {
			maxColour++;
			push(v, maxColour, -1);
		}
	}

	return 0;
}

int main() {

	int n = 0, m = 0, cnt = 0;
	cin >> n >> m;
	timer = 0;

	g.resize(n);
	used.resize(n, 0);
	tin.resize(n, 0);
	up.resize(n, 0);
	colours.resize(m);

	for (size_t i = 0; i < m; ++i) {
		int p = 0, q = 0;
		cin >> p >> q;

		p--;
		q--;

		g[p].push_back({ q, i });
		g[q].push_back({ p, i });
	}

	doSomething();


	cout << maxColour - 1 << endl;
	for (int i = 0; i < colours.size(); i++)
		cout << colours[i] - 1 << " ";

	cin >> n;
	return 0;
}