#include<bits/stdc++.h>
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
#define pii pair<ll,ll>
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
using namespace std;
bool Mbe;
ll read(){
    ll x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
void write(ll x){
    if(x<0)putchar('-'),x=-x;
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
const int N=2e5+9,Mod=998244353,G=3,iG=(Mod+1)/3;
int T,n,go[N<<3];
char s[N];
struct poly{
    vector<int>a;
    int size()const{return a.size();}
    void resize(int n){a.resize(n);}
    int operator[](int x)const{
        assert(0<=x&&x<(int)a.size());
        return a[x];
    }
    int &operator[](int x){
        assert(0<=x&&x<(int)a.size());
        return a[x];
    }
};
int pw(int x,int p){
    int res=1;
    while(p){
        if(p&1)res=1ll*res*x%Mod;
        x=1ll*x*x%Mod,p>>=1;
    }
    return res;
}
int init(int n){
    int p=1,c=0;
    while(p<=n)p<<=1,c++;
    go[0]=0;
    rep(i,1,p-1)go[i]=(go[i>>1]>>1)|((i&1)<<(c-1));
    return p;
}
void NTT(poly&a,int n,int sgn){
    rep(i,0,n-1){
        if(i>go[i])swap(a[i],a[go[i]]);
    }
    for(int i=1;i<n;i<<=1){
        int wn=pw((sgn==1?G:iG),(Mod-1)/(i<<1));
        for(int j=0;j<n;j+=(i<<1)){
            int w=1;
            rep(k,0,i-1){
                int x=a[j+k],y=1ll*a[j+k+i]*w%Mod;
                a[j+k]=(x+y)%Mod,a[j+k+i]=(x-y+Mod)%Mod;
                w=1ll*w*wn%Mod;
            }
        }
    }
    if(~sgn)return ;
    int iv=pw(n,Mod-2);
    rep(i,0,n-1)a[i]=1ll*a[i]*iv%Mod;
}
poly Brutemul(const poly&a,const poly&b){
    poly c;c.resize(a.size()+b.size()-1);
    rep(i,0,(int)a.size()-1){
        rep(j,0,(int)b.size()-1)c[i+j]=(c[i+j]+1ll*a[i]*b[j])%Mod;
    }
    return c;
}
poly operator*(const poly&a,const poly&b){
    if(a.size()+b.size()<=50)return Brutemul(a,b);
    int p=init(a.size()+b.size()-1);
    poly f=a,g=b;
    f.resize(p),g.resize(p);
    NTT(f,p,1),NTT(g,p,1);
    rep(i,0,p-1)f[i]=1ll*f[i]*g[i]%Mod;
    NTT(f,p,-1);
    f.resize(a.size()+b.size()-1);
    return f;
}
vector<array<int,2> >to[N];
int dp[N][3],len;
poly tr[N];
poly slv(int l,int r){
    if(l==r)return tr[l];
    int mid=(l+r)>>1;
    poly lef=slv(l,mid),rig=slv(mid+1,r);
    lef=lef*rig,vector<int>().swap(rig.a);
    return lef;
}
void dfs(int x,int fa,int up){
    if(s[x]=='S')dp[x][0]=dp[x][1]=1;
    else dp[x][1]=dp[x][2]=1;
    for(array<int,2>e:to[x]){
        int y=e[0],w=e[1];
        if(y==fa)continue;
        dfs(y,x,w);
    }
    len=1,tr[1]=(poly){{dp[x][0],dp[x][1],dp[x][2]}};
    for(array<int,2>e:to[x]){
        int y=e[0];
        if(y==fa)continue;
        tr[++len]=(poly){{dp[y][0],dp[y][1],dp[y][2]}};
    }
    poly prd=slv(1,len);
    rep(i,0,2)dp[x][i]=prd[len+i-1];
    if(fa){
        if(up)dp[x][0]=0;
        else dp[x][2]=0;
    }
}
bool Med;
int main(){
    cerr<<fabs(&Med-&Mbe)/1048576.0<<"MB\n";
    n=read();
    scanf("%s",s+1);
    rep(i,2,n){
        int x=read(),y=read();
        to[x].push_back({y,1});
        to[y].push_back({x,0});
    }
    dfs(1,0,-1);
    write(dp[1][1]);
    cerr<<"\n"<<clock()*1.0/CLOCKS_PER_SEC*1000<<"ms\n";
    return 0;
}