#include <bits/stdc++.h>
using namespace std;
//ifstream fin("input.in");
//ofstream fout("output.out");
#define N_MAX 500000
vector<int> gf_bus[N_MAX];
vector<int> gf_train[N_MAX];
set<int> gf_group[N_MAX];
int group[N_MAX], group_length[N_MAX];
void dfs_train(int pos, int gr) {
int i;
group[pos] = gr;
++group_length[gr];
for(i = 0; i < (int)gf_train[pos].size(); ++i) {
if(group[ gf_train[pos][i] ] == 0) {
dfs_train(gf_train[pos][i], gr);
}
}
}
int main()
{
int n, m, i, j, a, b, cnt;
char ch;
cin >> n >> m;
for(i = 0; i < m; ++i) {
cin >> a >> b >> ch;
--a, --b;
if(ch == 'T') {
gf_train[a].push_back(b);
gf_train[b].push_back(a);
}else{
gf_bus[a].push_back(b);
gf_bus[b].push_back(a);
}
}
cnt = 1;
for(i = 0; i < n; ++i) {
if(group[i] == 0) {
dfs_train(i, cnt++);
}
}
for(i = 0; i < n; ++i) {
for(j = 0; j < (int)gf_bus[i].size(); ++j) {
gf_group[group[i]].insert( group[gf_bus[i][j]] );
gf_group[ group[gf_bus[i][j]] ].insert(group[i]);
}
}
int rz = 0;
for(i = 1; i <= cnt; ++i) {
if( gf_group[i].size() == cnt - 2 ) {
rz += group_length[i];
}
}
cout << rz << '\n';
return 0;
}
