#include<bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;
template <class T> using V=vector<T>;
template <class T> using VV=V<V<T>>;

V<int> G[6060];
const int MOD=998244353;
 
int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  
  V<ll> P(6060);
  P[0]=1;
  for(int i=1;i<6060;i++) P[i]=P[i-1]*26%MOD;
  
  int n,m;
  cin>>n>>m;
  string s;
  cin>>s;
  ll cnt=0;
  rep(i,n) if(s[i]=='?') cnt++;
  rep(i,m){
    int a,b;
    cin>>a>>b;
    a--,b--;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  ll ans=0;
  rep(i,n){
    ll ca=0,ci=0,cq=0;
    for(auto v:G[i]){
      if(s[v]=='a') ca++;
      else if(s[v]=='i') ci++;
      else if(s[v]=='?') cq++;
    }
    if(s[i]=='o'){
      ans=(ans+ca*ci%MOD*P[cnt]%MOD)%MOD;
      if(cq) ans=(ans+ca*cq%MOD*P[cnt-1]%MOD)%MOD;
      if(cq) ans=(ans+cq*ci%MOD*P[cnt-1]%MOD)%MOD;
      if(cq>1) ans=(ans+cq*(cq-1)%MOD*P[cnt-2]%MOD)%MOD;
    }
    else if(s[i]=='?'){
      ans=(ans+ca*ci%MOD*P[cnt-1]%MOD)%MOD;
      if(cq) ans=(ans+ca*cq%MOD*P[cnt-2]%MOD)%MOD;
      if(cq) ans=(ans+cq*ci%MOD*P[cnt-2]%MOD)%MOD;
      if(cq>1) ans=(ans+cq*(cq-1)%MOD*P[cnt-3]%MOD)%MOD;
    }
  }
  cout<<ans<<endl;
  
  return 0;
}