#include <bits/stdc++.h>
using namespace std;
const int mxN = 5e5 + 100;
int par[mxN], sz[mxN], deg[mxN], par2[mxN], sz2[mxN];
set<pair<int, int>> bus;
int find(int u){
if(u == par[u]) return u;
return 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 find2(int u){
if(u == par2[u]) return u;
return par2[u] = find2(par2[u]);
}
void unite2(int u, int v){
u = find2(u), v = find2(v);
if(u == v) return;
par2[u] = v, sz2[v] += sz2[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, par2[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});
}
int rem = 0;
for(int i = 1; i <= n; ++i) rem += par[i] == i;
set<pair<int,int>> nbus;
for(auto it : bus){
it.first = find(it.first);
it.second = find(it.second);
if(it.first == it.second) continue;
nbus.insert({min(it.first, it.second), max(it.first, it.second)});
}
for(auto it : nbus){
//cout << it.first << " " << it.second << endl;
++deg[it.first], ++deg[it.second];
}
for(int i = 1; i <= n; ++i){
if(find(i) == i && deg[i] == rem - 1) ans += sz[find(i)];
}
cout << ans << endl;
return 0;
}
