#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
const long long mod = 1e9 + 7;

int n, m, a[maxn], dfn[maxn], low[maxn], id[maxn], idx, scc, val[maxn];
bool ins[maxn];
stack<int> stk;
vector<int> g[maxn];

void tarjan(int u) {
    dfn[u] = low[u] = ++idx;
    stk.push(u);
    ins[u] = true;
    for (auto v : g[u]) {
        if (!dfn[v]) {
            tarjan(v);
            low[u] = min(low[u], low[v]);
        }
        else if (ins[v])
            low[u] = min(low[u], dfn[v]);
    }
    if (low[u] == dfn[u]) {
        val[++scc] = 1e9 + 1;
        int v;
        do {
            v = stk.top();
            stk.pop();
            ins[v] = false;
            id[v] = scc;
            val[scc] = min(val[scc], v);
        } while (v != u);
    }
}

int main() {
    scanf("%d%d", &n, &m);
    while (m--) {
        int u, v;
        scanf("%d%d", &u, &v);
        g[u].push_back(v);
    }
    for (int i = 1; i <= n; i++)
        if (!dfn[i])
            tarjan(i);
    cout << scc << endl;
    for (int i = 1; i <= n; i++) {
        if (i > 1) cout << " ";
        cout << val[ id[i] ];
    }
    cout << endl;
    return 0;
}