#include <cstdio>
#include <vector>
#include <set>
#include <algorithm>
#include <map>
#include <queue>
using namespace std;
int N, M;
typedef pair<int, int> pt;
vector< vector< int > > G;
vector< set< int > > C;
vector<pt> Vhod;
map<pt, int> Izhod;
vector< bool > visited;
int maxColor = 1;

int getColor(int u, int v)
{
	int color = 1;
	set<int>::iterator it1 = C[u].begin();
	set<int>::iterator it2 = C[v].begin();
	while(it1 != C[u].end() || it2 != C[v].end())
	{
		bool change = false;
		if(it1 != C[u].end() && color == *it1)
		{
			it1++;
			color++;
			change = true;
		}
		if(it2 != C[v].end() && color == *it2)
		{
			it2++;
			color++;
			change = true;
		}
		if(change)
		{
			while(it1 != C[u].end() && *it1 < color)
				++it1;
			while(it2 != C[v].end() && *it2 < color)
				++it2;
		} else {
			break;
		}
	}
	C[u].insert(color);
	C[v].insert(color);
	return color;
}

void solve(int start)
{
	int u, v, color;
	queue<int> q;
	q.push(start);
	visited[start] = true;
	while(!q.empty())
	{
		u = q.front(); q.pop();
		sort(G[u].begin(), G[u].end());
		for(int i = 0; i < G[u].size(); ++i)
		{

			v = G[u][i];
			if(visited[v])
				continue;
			
			color = getColor(u, v);
			Izhod[make_pair(u,v)] = color; 
			if(maxColor < color)
				maxColor = color;
			q.push(v);
		}
		visited[u] = true;
	}
}
int main()
{
	freopen("gcoloring.in", "r", stdin);
	freopen("gcoloring.out", "w", stdout);
	int u, v;
	scanf("%d%d", &N, &M);
	G.resize(N + 1);
	visited.resize(N + 1);
	C.resize(N + 1);
	for(int i = 0; i < M; i++) 
	{
		scanf("%d%d", &u, &v);
		G[u].push_back(v);
		G[v].push_back(u);
		Vhod.push_back(make_pair(u,v));
	}
	solve(1);
	printf("%d\n", maxColor);
	for(int i = 0; i < Vhod.size(); ++i)
		printf(i != Vhod.size()- 1 ? "%d\n" : "%d", Izhod[Vhod[i]]);
	return 0;
}