#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 2e5+10,mod = 998244353;
int addv(int x,int y){return (x+y>=mod)?(x+y-mod):(x+y);}
int subv(int x,int y){return (x>=y)?(x-y):(x-y+mod);}
void add(int& x,int y){x = addv(x,y);}
void sub(int& x,int y){x = subv(x,y);}
int qpow(int a,int n){
    int res = 1; a%=mod;
    while(n){
        if(n&1)res = 1ll*res*a%mod;
        n>>=1; a = 1ll*a*a%mod;
    }
    return res;
}
int qinv(int a){return qpow(a,mod-2);}
//
int n; string s;
vector<int> e[MAXN];

int f[MAXN][3];
typedef array<int,2> pr;
map<pr,int> q;

struct Poly{
    vector<int>a;
    int n;
    Poly(int N=0){a.resize(N+1,0);n=N;}
    void split(int N){if(n>N){a.resize(N+1,0);n=N;}}
};
namespace NTT{
	const int MAXN = 2e6+10;
    int f[MAXN],g[MAXN],h[MAXN],rev[MAXN],N;
    void change(int* f,int N){for(int i=0;i<N;i++)if(i<rev[i])swap(f[i],f[rev[i]]);}
    void DFT(int* f,int N,int rev){
        change(f,N);
        for(int len=2;len<=N;len<<=1){
            int step=qpow(rev,(mod-1)/len);
            for(int i=0;i<N;i+=len){
                int w=1;
                for(int j=0;j<len/2;j++){
                    int x=f[i+j],y=f[i+j+len/2];
                    f[i+j]=addv(x,1ll*w*y%mod);
                    f[i+j+len/2] = subv(x,1ll*w*y%mod);
                    w=1ll*w*step%mod;
                }
            }
        }
    }
    Poly ntt(Poly F,Poly G){
        int n=F.n,m=G.n;N=1;
        while(N<=(n+m))N<<=1;
        for(int i=0;i<N;i++)f[i]=g[i]=h[i]=0;
      	for(int i=0;i<N;i++){
            rev[i]=rev[i>>1]>>1;
            if(i&1)rev[i]|=(N>>1);
        }
       	for(int i=0;i<=n;i++)f[i]=F.a[i];
        for(int i=0;i<=m;i++)g[i]=G.a[i];
        DFT(f,N,3);DFT(g,N,3);
       	for(int i=0;i<N;i++)h[i]=1ll*f[i]*g[i]%mod;
        DFT(h,N,qinv(3));
        int inv=qinv(N);
       	for(int i=0;i<N;i++)h[i]=1ll*h[i]*inv%mod;
        Poly ret(n+m);
      	for(int i=0;i<=n+m;i++)ret.a[i]=h[i];
        return ret;
    }
};
Poly operator*(Poly p1,Poly p2){return NTT::ntt(p1,p2);}

int arr[MAXN],tot;

Poly solve(int l,int r){
    if(l==r){
        Poly F(2); 
        for(int i=0;i<=2;i++)F.a[i] = f[arr[l]][i];
        return F;
    }
    int mid = (l+r)>>1;
    return solve(l,mid) * solve(mid+1,r);
}

void dfs(int u,int fa){
    if(s[u] == 'S'){
        f[u][0] = f[u][1] = 1;
    }else{
        f[u][1] = f[u][2] = 1;
    }
    for(auto v : e[u])if(v != fa)dfs(v,u);

    tot = 0; for(auto v : e[u])if(v != fa)arr[++tot] = v; arr[++tot] = u;
    Poly tmp = solve(1,tot);
    for(int x=-1;x<=1;x++)f[u][x+1] = tmp.a[tot+x];

    if(q.find((pr){u,fa}) == q.end()){
        f[u][0] = 0;
    }
    if(q.find((pr){fa,u}) == q.end()){
        f[u][2] = 0;
    }
    
}

int main(){
    ios::sync_with_stdio(false); cin.tie(0);

    cin>>n>>s; s = " "+s;
    for(int i=1,u,v;i<n;i++){
        cin>>u>>v;
        e[u].push_back(v); e[v].push_back(u);
        q[(pr){u,v}] = 1;
    }
    dfs(1,0);
    cout<<f[1][1]<<endl;
    return 0;
}