#include <bits/stdc++.h>
using namespace std;

struct Fastio
{
	template <typename T>
	inline Fastio operator>>(T &x)
	{
		x = 0;
		char c = getchar();
		while (c < ‘0‘ || c > ‘9‘)
			c = getchar();
		while (c >= ‘0‘ && c <= ‘9‘)
			x = (x << 3) + (x << 1) + (c ^ 48), c = getchar();
		return *this;
	}
	inline Fastio &operator<<(const char *str)
	{
		int cur = 0;
		while (str[cur])putchar(str[cur++]);
		return *this;
	}
	template <typename T>
	inline Fastio &operator<<(T x)
	{
		if (x == 0)
		{
			putchar(‘0‘);
			return *this;
		}
		if (x < 0) putchar(‘-‘), x = -x;
		static int sta[45];
		int top = 0;
		while (x) sta[++top] = x % 10, x /= 10;
		while (top) putchar(sta[top] + ‘0‘), --top;
		return *this;
	}

} io;

int n, m, rt, ans, cnt_node, cntn;

int cnt;
array<int, 2000005> head;
struct abc
{
	int from, to, nxt, idg;
};
array<abc, 2000005> dd;

array<int, 2000005> dfn, low;
stack<int> s, sp;

array<int, 2000005> id;

array<int, 2000005> Min;

inline void add(int u, int v, int idp)
{
	dd[++cnt].to = v;
	dd[cnt].from = u;
	dd[cnt].idg = idp;
	dd[cnt].nxt = head[u];
	head[u] = cnt;
}

#define js(x) x % 2 ? x + 1 : x - 1

void tarjan(int u, int fa)
{
	dfn[u] = low[u] = ++cnt_node;
	for (int i = head[u]; i; i = dd[i].nxt)
	{
		int v = dd[i].to;
		if(id[dd[i].idg]) continue;
		if (!dfn[v])
		{
			s.push(dd[i].idg);
			tarjan(v, u);
			low[u] = min(low[u], low[v]);
			if (low[v] >= dfn[u])
			{
				cntn++;
				int ret = INT_MAX;
				int tp;
				while(1)
				{
					tp = s.top();
					s.pop();
					id[tp] = cntn;
					ret = min(ret, tp);
					if(tp == dd[i].idg) break;
				}
				Min[cntn] = ret;
//				io << "\n";
			}
		}
		else if(v != fa)
		{
			s.push(dd[i].idg);
			low[u] = min(low[u], dfn[v]);
		}
	}
}

signed main()
{
	io >> n >> m;
	for(int i = 1; i <= m; ++i)
	{
		int u, v;
		io >> u >> v;
		add(u, v, i);
		add(v, u, i);
	}
	Min.fill(1);
	for(int i = 1; i <= n; ++i)
		if(!dfn[i]) tarjan(i, 0);
	io << cntn << "\n";	
	for(int i = 1; i <= m; ++i) io << Min[id[i]] << " ";
	return 0;
}

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