#include <atcoder/modint>
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using mint = atcoder::modint998244353;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

void solve() {
  ll n, m;
  string s;
  cin >> n >> m >> s;
  vector g(n, vector<ll>());
  rep(i, m) {
    ll a, b;
    cin >> a >> b, a--, b--;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  ll sum_q = 0;
  rep(i, n) sum_q += s[i] == '?';
  vector<mint> pow26(sum_q + 10, 0);
  pow26[0] = 1;
  rep(i, sum_q + 5) pow26[i + 1] = pow26[i] * 26;
  auto valid = [&](ll sz, ll i) -> bool {
    if (sz >= 3) {
      return false;
    }
    if (s[i] == '?') {
      return true;
    }
    if (sz == 0 && s[i] == 'a') {
      return true;
    }
    if (sz == 1 && s[i] == 'o') {
      return true;
    }
    if (sz == 2 && s[i] == 'i') {
      return true;
    }
    return false;
  };
  mint ans = 0;
  ll sz = 0, q = 0;
  vector<bool> visited(n, false);
  auto dfs = [&](auto self, ll u) -> void {
    if (!valid(sz, u)) {
      return;
    }
    visited[u] = true;
    sz += 1;
    q += s[u] == '?';
    if (sz == 3) {
      ans += pow26[sum_q - q];
    } else {
      for (const auto v : g[u]) {
        if (!visited[v]) {
          self(self, v);
        }
      }
    }
    q -= s[u] == '?';
    sz -= 1;
    visited[u] = false;
  };
  rep(u, n) dfs(dfs, u);
  cout << ans.val() << '\n';
}

int main() {
  std::cin.tie(nullptr);
  std::ios_base::sync_with_stdio(false);
  int T = 1;
  for (int t = 0; t < T; t++) {
    solve();
  }
  return 0;
}