#include <bits/stdc++.h>
using namespace std;
const int mxN = 5e5 + 100;
int par[mxN], sz[mxN], deg[mxN];
set<pair<int, int>> bus;
int find(int u){
return u == par[u] ? u : par[u] = find(par[u]);
}
void unite(int u, int v){
u = find(u), v = find(v);
if(u == v) return;
par[u] = v, sz[v] += sz[u];
}
int main(){
int n, m, u, v, ans = 0;
cin >> n >> m;
char ch;
for(int i = 1; i <= n; ++i) sz[i] = 1, par[i] = i;
for(int i = 0; i < m; ++i){
cin >> u >> v >> ch;
if(u > v) swap(u, v);
if(ch == 'T') unite(u, v);
else bus.insert({u, v});
}
for(auto it : bus) ++deg[find(it.first)], ++deg[find(it.second)];
for(int i = 1; i <= n; ++i){
if(find(i) == i && deg[i] == (n - 1)) ans += sz[find(i)];
}
cout << ans << "\n";
return 0;
}
