// JvThunder ORZ Template
#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define pii pair<int,int>
typedef long long ll;
using namespace std;
const int N = 5e5+5;
int n,m;
int par[N];
int sz[N];
int deg[N];
vector<pii> train;
vector<pii> bus;
int find(int x)
{
if(par[x]==x) return x;
return par[x] = find(par[x]);
}
void join(int a,int b)
{
int ra = find(a); int rb = find(b);
if(ra==rb) return;
par[rb] = ra;
sz[ra] += sz[rb];
sz[rb] = 0;
}
void solve()
{
cin >> n >> m;
for(int i=0;i<m;i++)
{
int a,b;
char type;
cin >> a >> b >> type;
if(type=='T') train.pb({a,b});
else bus.pb({a,b});
}
for(int i=1;i<=n;i++) par[i] = i, sz[i] = 1;
for(auto x:train) join(x.F,x.S);
int cc = 0;
for(int i=1;i<=n;i++) if(par[i]==i) cc++;
set<pii> s;
for(auto x:bus)
{
int a = find(x.F); int b = find(x.S);
if(a==b) continue;
s.insert({min(a,b),max(a,b)});
}
for(auto x:s)
{
int a = x.F; int b = x.S;
deg[a]++; deg[b]++;
}
int ans = 0;
for(int i=1;i<=n;i++)
{
if(i==par[i])
{
if(deg[i]==cc-1) ans += sz[i];
}
}
cout << ans << endl;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
solve();
return 0;
}
