#include <cstdio>
#include <string>
#include <algorithm>
#include <iostream>
using namespace std;
const int MAXV = 1020;
const int INF = 1e9;
int d[MAXV];
int n, m, k, ds;
bool vis[MAXV];
int G[MAXV][MAXV];
int getID(string s){
int num;
if(s[0] == 'G'){
s = s.substr(1, s.size()-1);
num = stoi(s);
num += n;
}else{
num = stoi(s);
}
return num;
}
void Dijkstral(int s){
fill(vis, vis+MAXV, false);
fill(d, d+MAXV, INF);
d[s] = 0;
for(int i=0; i<n+m; i++){
int u = -1, MIN = INF;
for(int j=1; j<=n+m; j++){
if(vis[j]==false && d[j]<MIN){
u = j;
MIN = d[j];
}
}
if(u == -1) return;
vis[u] = true;
for(int v=1; v<=n+m; v++){
if(vis[v]==false && G[u][v]!=INF){
if(d[v] > d[u] + G[u][v]){
d[v] = d[u] + G[u][v];
}
}
}
}
}
double getavg(){
double res = 0;
for(int i=1; i<=n; i++){
res += 1.0*d[i]/n;
}
return res;
}
int main(){
fill(G[0], G[0]+MAXV*MAXV, INF);
scanf("%d %d %d %d", &n, &m, &k, &ds);
string s1, s2;
int u, v, w;
for(int i=0; i<k; i++){
cin >> s1 >> s2 >> w;
u = getID(s1);
v = getID(s2);
G[u][v] = w;
G[v][u] = w;
}
double maxdis = -1, minavg = INF;
int index;
for(int i=n+1; i<=n+m; i++){
Dijkstral(i);
int mindis = INF;
int flag = 0;
for(int j=1; j<=n; j++){
if(d[j] > ds){
flag = 1;
break;
}
if(d[j] < mindis){
mindis = d[j];
}
}
if(flag) continue;
if(mindis > maxdis){
maxdis = mindis;
index = i - n;
minavg = getavg();
}else if(mindis == maxdis){
if(getavg() < minavg){
index = i - n;
minavg = getavg();
}
}
}
if(maxdis == -1){
printf("No Solution");
}else{
printf("G%d\n%.1f %.1f", index, maxdis, minavg);
}
return 0;
}