#include <bits/stdc++.h> using namespace std; #define For(i, a, b) for(int i = (a); i < (b); i++) #define rep(i, n) For(i, 0, n) #define rFor(i, a, b) for(int i = (a); i >= (b); i--) #define ALL(v) (v).begin(), (v).end() #define rALL(v) (v).rbegin(), (v).rend() using lint = long long; using ld = long double; int INF = 2000000000; lint LINF = 1000000000000000000; struct SetupIo { SetupIo() { ios::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(15); } } setupio; #include <atcoder/modint> using mint = atcoder::modint998244353; int main() { int n, m; string s; cin >> n >> m >> s; int cnt = 0; for (char c : s) { if (c == '?') { cnt++; } } vector<vector<int>> g(n); rep(i, m) { int a, b; cin >> a >> b; a--; b--; g[a].emplace_back(b); g[b].emplace_back(a); } vector<mint> pows(cnt + 1); pows[0] = 1; For(i, 1, cnt + 1) { pows[i] = pows[i - 1] * mint(26); } mint ans = 0; rep(v, n) { if (s[v] != 'o' && s[v] != '?') { continue; } for (int u : g[v]) { if (s[u] != 'a' && s[u] != '?') { continue; } for (int w : g[v]) { if (w == u) { continue; } if (s[w] != 'i' && s[w] != '?') { continue; } int cur = cnt - (s[u] == '?') - (s[v] == '?') - (s[w] == '?'); ans += pows[cur]; } } } cout << ans.val() << "\n"; }