#include <bits/stdc++.h>
#define rep(i,l,r) for(int i=l; i<=r; i++)
#define per(i,r,l) for(int i=r; i>=l; i--)
#define IOS {cin.tie(0);cout.tie(0);ios::sync_with_stdio(0);}
using namespace std;

typedef long long ll;
typedef pair<int,int> P;

const int N = 20010;
struct Edge {
    int to, next, flow;
} ed[N], tmp[N];

int head[N], sz = -1, cur[N], deep[N], s, t, vis[N], ksj[N];
vector<int> e[N];


void addEdge(int from, int to, int flow) {
    sz++;
    ed[sz].next = head[from];
    head[from] = sz;
    ed[sz].flow = flow;
    ed[sz].to = to;
}

void add(int u, int v, int flow) {
    addEdge(u, v, flow);
    addEdge(v, u, 0);
}

bool bfs() {
    queue <int> q;
    q.push(s);
    memset(deep, 0, sizeof(deep));
    deep[s] = 1;
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        for (int i = head[u]; i != -1; i = ed[i].next) {
            int v = ed[i].to;
            if (deep[v] == 0 && ed[i].flow > 0) {
                deep[v] = deep[u] + 1;
                q.push(v);
                if (v == t) return true;
            }
        }
    }
    return false;
}

int dfs(int u, int flow) {
    if (u == t) return flow;
    int rest = flow;
    for (int i = cur[u]; i != -1; i = ed[i].next) {
        int v = ed[i].to;
        if (deep[v] == deep[u] + 1 && ed[i].flow > 0 && rest) {
            int now = dfs(v, min(ed[i].flow, rest));
            if (!now) deep[v] = 0;
            rest -= now;
            ed[i].flow -= now;
            ed[i^1].flow += now;
            if (ed[i].flow) cur[u] = i;
            if (rest == 0) break;
        }
    }
    if (rest == flow) deep[u] = -1;
    return flow - rest;
}

int dinic() {
    int flow = 0;
    while (bfs()) {
        for (int i = 1; i <= t; i++) cur[i] = head[i];
        flow += dfs(s, 1e9);
    }
    return flow;
}
stack<int> stt;

int low[N], dfn[N], inst[N], cnt, bel[N], num;
void tarjan(int u) {
    dfn[u] = low[u] = ++cnt;
    stt.push(u), inst[u] = 1;
    for (auto v: e[u]) {
        if (!dfn[v]) tarjan(v), low[u] = min(low[u], low[v]);
        else if (inst[v]) low[u] = min(low[u], dfn[v]);
    }
    if (low[u] == dfn[u]) {
        int now;
        num++;
        do {
            now = stt.top();
            stt.pop();
            inst[now] = 0;
            bel[now] = num;
        } while (now != u);
    }
}

int fa[N];

bool solve(int u, int kk) {
    vis[u] = 1;
    // cout <<u<<"$"<<endl;
    for (int i = head[u]; i!=-1; i = ed[i].next) {
        int v = ed[i].to;
        if (vis[v]) continue;
        
        if (ed[i^1].flow == 0) continue;
// cout<<"#";
        ed[i^1].flow--;
        // cout << v<<' '<<t<<"$"<<endl;
        if (v == t) {
            fa[kk] = u-num;
            // cout <<"#";
            return true;
        }
        if (solve(v, kk)) return true;
        ed[i^1].flow++;
    }
    return false;
}
int find(int x) {
    return x == fa[x]? x: find(fa[x]);
}
int main() {
    memset(head, -1, sizeof(head));
    int n, m;
    scanf("%d%d", &n, &m);
    
    rep (i, 1, m) {
        int u, v; scanf("%d%d", &u, &v);
        tmp[i].to = u;
        tmp[i].next = v;
        e[u].push_back(v);
        // e[v].push_back(u);
    }
    rep (i, 1, n) {
        if (!dfn[i]) tarjan(i);
    }
    s = 2*num + 1, t = s+1;
    rep (i, 1, t) fa[i] =i;
    // cout<<m
    rep (i, 1, m) {
        int u = tmp[i].to, v = tmp[i].next;
        
        if (bel[u] != bel[v]) {
            //  cout <<bel[u]<<' '<<bel[v]<<"#"<<endl;

            add(bel[u], bel[v]+num, 1e9);
            add(bel[u]+num, bel[v]+num, 1e9);
        }
    }
    
    rep (i, 1, num) {
        add(s, i, 1);
        add(i+num, t, 1);
    }
    // cout << num - dinic()<<endl;
    dinic();
    int kk = 0;
    for (int i = head[s]; i != -1; i = ed[i].next) {
        if (ed[i].flow == 1) ksj[ed[i].to] = ++kk;//, cout << ed[i].to<<"%\n";
    }
    cout <<kk<<endl;
    for (int i = head[s]; i != -1; i = ed[i].next) {
        if (ed[i].flow == 0) memset(vis, 0, sizeof(vis)), solve(ed[i].to, ed[i].to);
    }
    rep (i, 1, n) {
        cout << ksj[find(bel[i])]<<' ';
    }

    return 0;
}