f.cpp

//#define __GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for(int i = 0; i < (int)(n); ++i)
#define pb push_back
#define ALL(a) (a.begin()), (a.end())
#define mp make_pair
#define F first
#define S second
#define SZ(a) ((int)(a.size()))

typedef long long ll;
typedef pair<int, int> PI;

struct UF{
  vector<int> ap;
  UF(int n): ap(n){
      rep(i, n) ap[i] = i;
  }

  int find(int x){
    if(ap[x] == x)
      return x;
    return ap[x] = find(ap[x]);
  }

  void unit(int a, int b){
    ap[find(a)] = find(b);
  }
};

int n, m, k;

vector<PI> aG[300], bG[300];

void solve(){
  rep(i, n) aG[i].clear();
  rep(i, n) bG[i].clear();
  vector<pair<int, PI> > aed, bed;
  rep(i, m){
    int a, b, c;
    char ch;
    cin >> a >> b >> c >> ch;
    --a, --b;
    if(ch == 'A'){
      aed.pb(mp(c, mp(a, b)));
      aG[a].pb(mp(b, c));
      aG[b].pb(mp(a, c));
    }else{
      bed.pb(mp(c, mp(a, b)));
      bG[b].pb(mp(a, c));
      bG[a].pb(mp(b, c));
    }
  }

  vector<bool> usea(SZ(aed));
  vector<bool> useb(SZ(bed));
  sort(ALL(bed));
  sort(ALL(aed));
  UF uf(n);
  int cost = 0;
  rep(i, SZ(bed)){
    int a = bed[i].S.F;
    int b = bed[i].S.S;
    if(uf.find(a) == uf.find(b)) continue;
    uf.unit(a, b);
    useb[i] = 1;
    cost += bed[i].F;
  }

  int useaed = 0;
  rep(i, SZ(aed)){
    int a = aed[i].S.F;
    int b = aed[i].S.S;
    if(uf.find(a) == uf.find(b)) continue;
    uf.unit(a, b);
    usea[i] = 1;
    cost += aed[i].F;
    useaed += 1;
  }

  {
    bool ok = true;
    rep(i, n) ok &= uf.find(i) == uf.find(0);
    if(!ok || useaed > k){
      cout << -1 << endl;
      return;
    }
  }

  while(useaed < k){
    vector<pair<int, PI> > ap;
    rep(i, SZ(bed)){
      if(!useb[i]) continue;
      UF uf(n);
      rep(j, SZ(bed)){
        if(i == j || !useb[j]) continue;
        int a = bed[j].S.F;
        int b = bed[j].S.S;
        uf.unit(a, b);
      }
      rep(j, SZ(aed)){
        if(!usea[j]) continue;
        int a = aed[j].S.F;
        int b = aed[j].S.S;
        uf.unit(a, b);
      }

      rep(j, SZ(aed)){
        if(usea[j]) continue;
        int a = aed[j].S.F;
        int b = aed[j].S.S;
        if(uf.find(a) == uf.find(b)) continue;
        ap.pb(mp(aed[j].F - bed[i].F, mp(i, j)));
        break;
      }
    }
    if(ap.empty()) break;
    sort(ALL(ap));
    ++useaed;
    useb[ap[0].S.F] = false;
    usea[ap[0].S.S] = true;
    cost += ap[0].F;
  }

  if(useaed == k)
    cout << cost << endl;
  else
    cout << -1 << endl;
}

int main(int argc, char *argv[])
{
  while(cin >> n >> m >> k && n) solve();
  return 0;
}