#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#define N 500000
using namespace std;
const int inf=(int)(1e9);
int read()
{
	char c=0;
	int sum=0;
	while (c<'0'||c>'9') c=getchar();
	while ('0'<=c&&c<='9') sum=sum*10+c-'0',c=getchar();
	return sum;
}
struct reads
{
	int x,y,z,cl;
	bool operator < (const reads &t)const
	{
		return z>t.z;
	}
};
reads ed[N+1];
int n,m,k,s,rt[N+1];
bool used[N+1];
long long ans;
int find(int x)
{
	if (rt[x]==x) return x;
	return rt[x]=find(rt[x]);
}
void unionn(int x,int y)
{
	rt[x]=y;
	return;
}
bool check(int x)
{
	int l=0,r=0;
	for (int i=1;i<=n;++i) rt[i]=i;
	for (int i=1;i<=x-1;++i)
		if (used[i]&&find(ed[i].x)!=find(ed[i].y))
			unionn(find(ed[i].x),find(ed[i].y));
	for (int i=x;i<=m;++i)
		if (!ed[i].cl&&find(ed[i].x)!=find(ed[i].y))
			unionn(find(ed[i].x),find(ed[i].y));
	for (int i=x;i<=m;++i)
		if (ed[i].cl&&find(ed[i].x)!=find(ed[i].y))
			l++,unionn(find(ed[i].x),find(ed[i].y));
	for (int i=1;i<=n;++i) rt[i]=i;
	for (int i=1;i<=x-1;++i)
		if (used[i]&&find(ed[i].x)!=find(ed[i].y))
			unionn(find(ed[i].x),find(ed[i].y));
	for (int i=x;i<=m;++i)
		if (ed[i].cl&&find(ed[i].x)!=find(ed[i].y))
			r++,unionn(find(ed[i].x),find(ed[i].y));
	for (int i=x;i<=m;++i)
		if (!ed[i].cl&&find(ed[i].x)!=find(ed[i].y))
			unionn(find(ed[i].x),find(ed[i].y));
	for (int i=1;i<=n;++i)
		if (find(i)!=find(1))
			return 0;
	return l<=k&&k<=r;
}
int main()
{
	n=read(),m=read(),k=read(),s=read();
	for (int i=1;i<=m;++i)
	{
		ed[i].x=read(),ed[i].y=read(),ed[i].z=read();
		if (ed[i].x==s||ed[i].y==s) ed[i].cl=1;
	}
	if (!check(1))
	{
		puts("nonnondayo");
		return 0;
	}
	sort(ed+1,ed+m+1);
	for (int i=1;i<=m;++i)
		if (!check(i+1))
			ans+=ed[i].z,used[i]=1,k-=ed[i].cl;
	printf("%lld\n",ans);
	return 0;
}