#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  VVI to(n);
  rep(_, m) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    to[u].emplace_back(v);
    to[v].emplace_back(u);
  }
  vector<pair<map<int, mint>, mint>> dp(n);
  mint ans;
  dsu uf(n);
  rep(v, n) {
    dp[v].first[v] = 1;
    int vl = v;
    for (int u : to[v]) if (u < v) {
      int ul = uf.leader(u);
      if (ul == vl) continue;
      if (dp[ul].first.size() > dp[vl].first.size()) {
        swap(dp[ul], dp[vl]);
      }
      for (auto [i, c] : dp[ul].first) {
        auto it = dp[vl].first.find(i);
        if (it == dp[vl].first.end()) dp[vl].first[i] = c + dp[ul].second - dp[vl].second;
        else {
          it->second += c + dp[ul].second;
        }
      }
      // if (v == 2) exit(0);
      dp[ul].first.clear();
      int l = uf.merge(ul, vl);
      if (vl != l) {
        dp[l] = move(dp[vl]);
        vl = l;
      }
    }
    mint val = dp[vl].first[v] + dp[vl].second;
    ans += val;
    // cout << v << ' ' << val.val() << endl;
    for (int u : to[v]) if (u > v) {
      auto it = dp[vl].first.find(u);
      if (it == dp[vl].first.end()) dp[vl].first[u] = -dp[vl].second;
    }
    dp[vl].second += val;
    // if (v == 1) cout << (dp[vl].first[2] + dp[vl].second).val() << endl, exit(0);
  }
  cout << ans.val() << '\n';
}