#include <bits/stdc++.h>
std::mt19937 rng(
    (int)std::chrono::steady_clock::now().time_since_epoch().count());
using namespace std;
long long mod = (998244353LL);
inline long long Mod(long long a, long long b) { return (a % b); }
inline long long poww(long long a, long long b) {
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = (res * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return res;
}
long long gcd(long long a, long long b) {
  while (b) {
    a %= b, swap(a, b);
  }
  return a;
}
void read(vector<int> &w, int n) {
  w.resize(n);
  for (int i = 0; i < n; i++) cin >> w[i];
}
void print(vector<int> &w) {
  for (int i = 0; i < (int)(w).size(); i++) {
    if (i == (int)(w).size() - 1)
      cout << w[i] << "\n";
    else
      cout << w[i] << " ";
  }
}
int prodmod(vector<int> w);
int summod(vector<int> w);
int n, m, q, k, v[200010];
string second;
pair<int, int> w[200010];
vector<pair<int, int>> grafo[200010];
long long dist[200010][20][2];
void solve() {
  priority_queue<vector<long long>, vector<vector<long long>>,
                 greater<vector<long long>>>
      pq;
  pq.push({0, 1, 0, 0});
  dist[1][0][0] = 0;
  while (!pq.empty()) {
    auto curr = pq.top();
    pq.pop();
    long long d = curr[0], x = curr[1], q = curr[2], flag = curr[3];
    if (d > dist[x][q][flag]) continue;
    for (auto v : grafo[x]) {
      int T = (v.second != flag);
      int qq = q + T, flag2 = v.second;
      if (qq < 20 and
          dist[v.first][qq][flag2] >
              dist[x][q][flag] + 1 + (1LL * T) * (1LL << (1LL * q))) {
        dist[v.first][qq][flag2] =
            dist[x][q][flag] + 1 + (1LL * T) * (1LL << (1LL * q));
        pq.push({dist[v.first][qq][flag2], v.first, qq, flag2});
      }
    }
  }
}
pair<int, int> dist2[200010][2];
const int inf = 0x3f3f3f3f;
int32_t main() {
  memset(dist, inf, sizeof dist);
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m;
  for (int i = 1, a, b; i <= m; i++) {
    cin >> a >> b;
    grafo[a].push_back({b, 0});
    grafo[b].push_back({a, 1});
  }
  solve();
  long long ans = inf;
  for (int i = 0; i < 20; i++) ans = min({ans, dist[n][i][0], dist[n][i][1]});
  if (ans != inf)
    cout << ans % mod << "\n", exit(0);
  else {
    for (int i = 0; i < 200010; i++) dist2[i][0] = dist2[i][1] = {inf, inf};
    priority_queue<vector<int>, vector<vector<int>>, greater<vector<int>>> pq;
    pq.push({0, 0, 1, 0});
    dist2[1][0] = {0, 0};
    while (!pq.empty()) {
      auto curr = pq.top();
      pq.pop();
      int inv = curr[0], d = curr[1], x = curr[2], flag = curr[3];
      if (pair<int, int>(inv, d) > dist2[x][flag]) continue;
      for (auto v : grafo[x]) {
        pair<int, int> novo = {inv + (v.second != flag), d + 1};
        if (novo < dist2[v.first][v.second]) {
          dist2[v.first][v.second] = novo;
          pq.push({inv + (v.second != flag), d + 1, v.first, v.second});
        }
      }
    }
    pair<int, int> curr = min(dist2[n][0], dist2[n][1]);
    int ans = curr.second, pot = 1LL;
    for (int i = 0; i < curr.first; i++) {
      ans += pot;
      ans %= mod;
      pot *= 2LL;
      pot %= mod;
    }
    cout << ans % mod << "\n";
  }
}
int summod(vector<int> w) {
  int curr = 0;
  for (int i = 0; i < (int)(w).size(); i++) {
    curr = (curr + w[i]) % mod;
    if (curr < 0) curr += mod;
  }
  return curr;
}
int prodmod(vector<int> w) {
  int curr = 1;
  for (int i = 0; i < (int)(w).size(); i++) {
    if (w[i] >= mod) w[i] %= mod;
    curr = (curr * w[i]) % mod;
    if (curr < 0) curr += mod;
  }
  return curr;
}
