#include <bits/stdc++.h>

using namespace std;

const int maxn = 2e5 + 5;
const int base = 1;
const int INF = 998244353;

int n;
int f[maxn][3];
vector<pair<int, int> > tree[maxn];
char s[maxn];

inline void dfs(int u, int p) {
	int g[3] = {0, 1, 0}, dir = 0;
	for (auto e: tree[u]) {
		int v = e.first;
		if (v != p){
			dfs(v, u);
			int ng[3] = {0, 0, 0};
			for (int i = -1; i <= 1; ++i) if (g[i + base]) {
				for (int j = -1; j <= 1; ++j) if (f[v][j + base] && abs(i + j) <= 1)
					ng[i + j + base] = (ng[i + j + base] + 1ll * g[i + base] * f[v][j + base]) % INF;
			}
			memcpy(g, ng, sizeof(ng));
		} else dir = e.second;
	}
	
	int have = (s[u] == 'S');
	
	if (dir == 0) {
		if (have) f[u][0 + base] = (g[0 + base] + g[-1 + base]) % INF;
		else f[u][0 + base] = (g[0 + base] + g[1 + base]) % INF;
	}
	else if (dir == -1) {
		if (have) {
			f[u][0 + base] = (g[0 + base] + g[-1 + base]) % INF;
			f[u][-1 + base] = g[-1 + base];
		} else {
			f[u][-1 + base] = (g[-1 + base] + g[0 + base]) % INF;
			f[u][0 + base] = g[0 + base];
		}
	}
	else {
		if (have) {
			f[u][1 + base] = (g[0 + base] + g[1 + base]) % INF;
			f[u][0 + base] = (g[0 + base] + g[-1 + base]) % INF;
		}
		else {
			f[u][0 + base] = (g[0 + base] + g[1 + base]) % INF;
			f[u][1 + base] = g[1 + base];
		}
	}
	
	// printf("u = %d f = (%d %d %d)\n", u, f[u][-1 + base], f[u][0 + base], f[u][1 + base]);
}

int main(){
	scanf("%d", &n);
	scanf("%s", s);
	for (int i = 1; i < n; ++i) {
		int u, v; scanf("%d%d", &u, &v);
		--u, --v;
		tree[u].push_back(make_pair(v, 1));
		tree[v].push_back(make_pair(u, -1));
	}
	
	dfs(0, -1);
	
	printf("%d\n", f[0][0 + base]);
	return 0;
}