#include<bits/stdc++.h>
using namespace std;
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#define pb push_back
#define all(a) begin(a),end(a)
#define allr(a) rbegin(a),rend(a)
#define ff first
#define ss second
template<class T> bool chmax(T& a,T b){return a<b?a=b,1:0;}
template<class T> bool chmin(T& a,T b){return a>b?a=b,1:0;}
using ll =long long;
using pii =pair<int,int>;
using pll=pair<long long,long long>;
using vi=vector<int>;
using vll=vector<ll>;
inline bool ingrid(int a,int b,int h,int w){
    return 0<=a&&a<h&&0<=b&&b<w;
}

const int INFI = numeric_limits<int>::max() / 2; const long long INFL = numeric_limits<long long>::max() / 2;
constexpr pii dx4[4] = {pii{-1, 0}, pii{0, -1},pii{1, 0}, pii{0, 1} };
#define endl '\n'

int n,m;
string s;
vi a,b;
void solve(){
    const ll mod=998244353;
    vector<ll> pow26(n+1);
    pow26[0]=1;
    rep(i,1,n+1){
        pow26[i]=pow26[i-1]*26%mod;
    }
    vector g(n,vector<int>());
    rep(i,0,m){
        g[a[i]].pb(b[i]);
        g[b[i]].pb(a[i]);
    }
    int cnt{};
    rep(i,0,n)cnt+=s[i]=='?';
    ll ans{};
    rep(j,0,n){
        fore(i,g[j]){
            fore(k,g[j]){
                if(i==k)continue;
                if(s[i]!='?'&&s[i]!='a')continue;
                if(s[j]!='?'&&s[j]!='o')continue;
                if(s[k]!='?'&&s[k]!='i')continue;
                int q=cnt-(s[i]=='?')-(s[j]=='?')-(s[k]=='?');
                ans+=pow26[q];
                ans%=mod;
            }
        }
    }
    cout<<ans<<endl;
}

int main(){
    cin>>n>>m>>s;
    a.resize(m);b.resize(m);
    rep(i,0,m){
        cin>>a[i]>>b[i];
        a[i]--;b[i]--;
    }
    solve();
    return 0;
}
/*

*/