#include<bits/stdc++.h>
using namespace std;
const int N=5e5+5,inf=1e9+7;
typedef long long ll;
int n,m,k,s,mn[N],fa[N],ce;
ll ans;
vector<pair<int,int> >e1,e2;
struct edge{
	int x,y,z;
	bool operator <(const edge a)const{return z<a.z;}
}e[N];
int gf(int x){
	return fa[x]==x?fa[x]:fa[x]=gf(fa[x]);
}
int main(){
	scanf("%d%d%d%d",&n,&m,&k,&s);
	for(int i=1;i<=n;++i)fa[i]=i,mn[i]=inf;
	for(int i=1,x,y,z;i<=m;++i){
		scanf("%d%d%d",&x,&y,&z);
		if(x==s)mn[y]=min(mn[y],z);
		else if(y==s)mn[x]=min(mn[x],z);
		else e[++ce]={x,y,z};
	}
	sort(e+1,e+ce+1);
	for(int i=1;i<=ce;++i){
		int x=gf(e[i].x),y=gf(e[i].y);
		if(x==y)continue;
		if(e[i].z>=max(mn[x],mn[y]))e1.emplace_back(e[i].z,max(mn[x],mn[y]));
		else e2.emplace_back(max(mn[x],mn[y]),e[i].z);
		fa[x]=y,mn[y]=min(mn[y],mn[x]);
		ans+=e[i].z;
	}
	for(int i=1;i<=n;++i)if(i!=s&&fa[i]==i){
		if(mn[i]==inf)return puts("nonnondayo"),0;
		ans+=mn[i],--k;
	}
	if(k<0)return puts("nonnondayo"),0;
	sort(e1.begin(),e1.end(),greater<pair<int,int> >());
	sort(e2.begin(),e2.end());
	for(auto v:e1)if(k)ans+=v.second-v.first,--k;
	for(auto v:e2)if(k)ans+=v.first-v.second,--k;
	if(k)return puts("nonnondayo"),0;
	printf("%lld\n",ans);
	return 0;
}