#include <bits/stdc++.h>
using namespace std;
const int N = 4e5 + 5;
vector<int> g[N];
int low[N], dis[N], timer = 0, vis[N] = {0};
int disjoint[N] = {0}, labels[N];
vector<int> bridgeTree[N];
vector<pair<int, int> > bridgeNode[N];
map<pair<int, int>, int> bridg;
map<pair<int, int>, int> id;
vector<pair<int, int> > edge;
void dfs(int s, int p) {
  low[s] = dis[s] = timer++;
  vis[s] = 1;
  for (auto i : g[s]) {
    if (!vis[i]) {
      dfs(i, s);
      low[s] = min(low[s], low[i]);
      if (dis[s] < low[i]) {
        bridg[make_pair(min(i, s), max(i, s))] = 1;
      }
    } else if (i != p) {
      low[s] = min(low[s], dis[i]);
    }
  }
}
void connectedComponents(int s, int lbl) {
  labels[s] = lbl;
  disjoint[lbl]++;
  vis[s] = 1;
  for (auto i : g[s])
    if (!vis[i]) {
      if (bridg[make_pair(min(i, s), max(i, s))]) continue;
      connectedComponents(i, lbl);
    }
}
void joinComponent(int s, int p, int lbl) {
  vis[s] = 1;
  for (auto i : g[s]) {
    if (vis[i] == 2 || i == p || bridg[make_pair(min(i, s), max(i, s))])
      continue;
    int idx = id[make_pair(min(i, s), max(i, s))];
    edge[idx] = make_pair(s, i);
    if (vis[i] == 0) joinComponent(i, s, lbl);
  }
  vis[s] = 2;
}
void buildTree(int s) {
  vis[s] = 1;
  for (auto i : g[s]) {
    if (vis[i]) continue;
    if (bridg[make_pair(min(i, s), max(i, s))]) {
      bridgeTree[labels[s]].push_back(labels[i]),
          bridgeNode[labels[s]].push_back(make_pair(s, i));
      bridgeTree[labels[i]].push_back(labels[s]),
          bridgeNode[labels[i]].push_back(make_pair(i, s));
    }
    buildTree(i);
  }
}
void bridgeDfs(int s, int p) {
  for (int i = 0; i < (int)bridgeTree[s].size(); i++) {
    int lbl = bridgeTree[s][i], u = bridgeNode[s][i].first,
        v = bridgeNode[s][i].second;
    if (lbl == p) continue;
    int idx = id[make_pair(min(u, v), max(u, v))];
    edge[idx] = make_pair(v, u);
    bridgeDfs(lbl, s);
  }
}
int solve(int n) {
  memset(vis, 0, sizeof(vis));
  for (int j = 1; j <= n; j++)
    if (!vis[j]) dfs(j, 0);
  int lbl = 1;
  memset(vis, 0, sizeof(vis));
  for (int j = 1; j <= n; j++)
    if (!vis[j]) connectedComponents(j, lbl++);
  memset(vis, 0, sizeof(vis));
  for (int j = 1; j <= n; j++)
    if (!vis[j]) joinComponent(j, 0, labels[j]);
  int mx = 0, src = -1;
  for (int j = 1; j < lbl; j++)
    if (disjoint[j] > mx) mx = disjoint[j], src = j;
  memset(vis, 0, sizeof(vis));
  buildTree(1);
  bridgeDfs(src, 0);
  return mx;
}
int main() {
  ios_base ::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  for (int j = 0; j < m; j++) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
    id[make_pair(min(u, v), max(u, v))] = j;
    edge.push_back(make_pair(u, v));
  }
  cout << solve(n) << endl;
  for (auto i : edge) cout << i.first << " " << i.second << endl;
  return 0;
}
