#include <bits/stdc++.h>
using namespace std;
using ll = unsigned long long;
#define all(x) (x).begin(), (x).end()

namespace NTT
	{
		const ll g=3, p=998244353;
		const int N=1<<22;
		ll inv[N], fac[N], ifac[N];
		void getfac(int n)
		{
			static int pre=-1;
			if (pre==-1) pre=1, ifac[0]=fac[0]=fac[1]=ifac[1]=inv[1]=1;
			if (n<=pre) return;
			for (int i=pre+1, j; i<=n; i++)
			{
				j=p/i;
				inv[i]=(p-j)*inv[p-i*j]%p;
				fac[i]=fac[i-1]*i%p;
				ifac[i]=ifac[i-1]*inv[i]%p;
			}
			pre=n;
		}
		ll w[N];
		int r[N];
		ll ksm(ll x, ll y)
		{
			ll r=1;
			while (y)
			{
				if (y&1) r=r*x%p;
				x=x*x%p;
				y>>=1;
			}
			return r;
		}
		void init(int n)
		{
			static int pr=0, pw=0;
			if (pr==n) return;
			int b=__lg(n)-1, i, j, k;
			for (i=1; i<n; i++) r[i]=r[i>>1]>>1|(i&1)<<b;
			if (pw<n)
			{
				for (j=1; j<n; j=k)
				{
					k=j*2;
					ll wn=ksm(g, (p-1)/k);
					w[j]=1;
					for (i=j+1; i<k; i++) w[i]=w[i-1]*wn%p;
				}
				pw=n;
			}
			pr=n;
		}
		int cal(int x) { return 1<<__lg(max(x, 1)*2-1); }
		struct Q:vector<ll>
		{
			bool flag;
			Q &operator%=(int n) { assert((n&-n)==n); resize(n); return *this; }
			Q operator%(int n) const
			{
				assert((n&-n)==n);
				if (size()<=n)
				{
					auto f=*this;
					return f%=n;
				}
				return Q(vector(begin(), begin()+n));
			}
			int deg() const
			{
				int n=size()-1;
				while (n>=0&&begin()[n]==0) --n;
				return n;
			}
			explicit Q(int x=1, bool f=0):flag(f), vector<ll>(cal(x)) { }
			Q(const vector<ll> &o, bool f=0):Q(o.size(), f) { copy(all(o), begin()); }
			void dft()
			{
				int n=size(), i, j, k;
				ll y, *f, *g, *wn, *a=data();
				init(n);
				for (i=1; i<n; i++) if (i<r[i]) ::swap(a[i], a[r[i]]);
				for (k=1; k<n; k*=2)
				{
					wn=w+k;
					for (i=0; i<n; i+=k*2)
					{
						g=(f=a+i)+k;
						for (j=0; j<k; j++)
						{
							y=g[j]*wn[j]%p;
							g[j]=f[j]+p-y;
							f[j]+=y;
						}
					}
					if (k*2==n||k==1<<14) for (i=0; i<n; i++) a[i]%=p;
				}
				if (flag)
				{
					y=ksm(n, p-2);
					for (i=0; i<n; i++) a[i]=a[i]*y%p;
					reverse(a+1, a+n);
				}
				flag^=1;
			}
        };
        Q &operator*=(Q &f, Q g)
		{
			if (f.flag|g.flag)
			{
				int n=f.size(), i;
				assert(n==g.size());
				if (!f.flag) f.dft();
				if (!g.flag) g.dft();
				for (i=0; i<n; i++) (f[i]*=g[i])%=p;
				f.dft();
			}
			else
			{
				int n=cal(f.size()+g.size()-1), i, j;
				int m1=f.deg(), m2=g.deg();
				if ((ll)m1*m2>(ll)n*__lg(n)*8)
				{
					(f%=n).dft(); (g%=n).dft();
					for (i=0; i<n; i++) (f[i]*=g[i])%=p;
					f.dft();
				}
				else
				{
					vector<ll> r(max(0, m1+m2+1));
					for (i=0; i<=m1; i++) for (j=0; j<=m2; j++) (r[i+j]+=f[i]*g[j])%=p;
					f=Q(n);
					copy(all(r), f.begin());
				}
			}
			return f;
		}
    }

using NTT::Q, NTT::p;

const int N = 2e5+5;
vector<pair<int,int>> G[N];
int col[N];
ll f[N][3];

void dfs(int x, int fa, int tfc)
{
    int siz=0;
    vector<Q> son;
    for(auto [y, tyc] : G[x]) if(y != fa)
    {
        ++siz;
        dfs(y, x, 1-tyc);
        son.push_back(Q({f[y][2], f[y][0], f[y][1]}));
        // son.push_back({y, tyc});
    }
    if(siz == 0)
    {
        f[x][0] = 1;
        if (tfc == col[x]) f[x][2-tfc] = 1;
        // cerr << x << " " << f[x][0] << " " << f[x][1] << " " << f[x][2] << "\n";
        return ;
    }
    // 1 : S out F in
    // 2 : F out S in
    
    while(son.size() != 1)
    {
        vector<Q> tmp;
        for(int i=0;i<son.size();i+=2) 
        {
            if(i+1<son.size()) son[i]*=son[i+1];
            tmp.push_back(son[i]);
        }
        son=tmp;
    }
    Q res=son[0];
    // for(int i=0;i<=siz*2;++i) cerr<<i<<":"<<res[i]<<" "; cerr<<"\n";
    
    f[x][0] = (res[siz] + res[siz+(col[x]==1?-1:1)]) % p; 
    
    if(tfc == 1)
    {
        if(!col[x]) f[x][1] = (res[siz+1] + (siz>=2?res[siz+2]:0ll)) % p;
        else f[x][1] = (res[siz] + res[siz+1]) % p;
    }
    
    if(tfc == 0)
    {
        if(col[x]) f[x][2] = (res[siz-1] + (siz>=2?res[siz-2]:0ll)) % p;
        else f[x][2] = (res[siz] + res[siz-1]) % p;
    }
    
    // cerr << x << " " << f[x][0] << " " << f[x][1] << " " << f[x][2] << "\n";
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    
    int n;
    cin>>n;
    string s; cin>>s;
    for(int i=1; i<=n; ++i) col[i]=(s[i-1]=='S');
    for(int i=1; i<n; ++i) 
    {
        int x, y;
        cin>>x>>y;
        G[x].push_back({y, 1});
        G[y].push_back({x, 0});
    }
    dfs(1, 0, 0);
    cout << f[1][0] << "\n";
}