#include<bits/stdc++.h>
#define pii pair<int,int>
#define fi first
#define se second
#define ll long long
#define pb push_back
#define mp make_pair
using namespace std;
bool vis[50004];
struct Node{int u,v,w;}e[500004],e1[500004];
bool operator<(Node a,Node b){return a.w>b.w;}
int n,m,s,k,ct,tt;ll Ans;
vector<pii>vec[2000005];
struct DSU{
	int fa[50004],sz[50004],Ct;
	pii stk[500004];int col[500004],tail;
	void init(){for(int i=1;i<=n;++i)fa[i]=i,sz[i]=1;Ct=n;}
	int find(int r){
		if(r==fa[r])return r;
		return find(fa[r]);
	}
	void merge(int u,int v,int t){
		u=find(u),v=find(v);if(u==v)return;
	    --Ct;if(sz[u]<sz[v])swap(u,v);sz[u]+=sz[v];
	    stk[++tail]=mp(u,v),col[tail]=t;fa[v]=u;
	}
	void back(int p){
		while(tail&&col[tail]==p){
			int u=stk[tail].fi,v=stk[tail].se;--tail;
			sz[u]-=sz[v],fa[v]=v,++Ct;
		}
	}
}t,t1;
#define ls (p<<1)
#define rs (p<<1|1)
#define mid (l+r>>1)
void ins(int p,int l,int r,int a,pii v){
	if(a>r)return;
	if(a<=l){vec[p].pb(v);return;}
	if(a<=mid)ins(ls,l,mid,a,v);
	ins(rs,mid+1,r,a,v);
}
void Ins(int p,int l,int r,int b,pii v){
	if(b<l)return;
	if(r<=b){vec[p].pb(v);return;}
	if(b>mid)Ins(rs,mid+1,r,b,v);
	Ins(ls,l,mid,b,v);
}
bool chk(){
	if(ct<k||t.Ct>1||t1.Ct>k+1)return 0;
	return 1;
}
void solve(int p,int l,int r){
	for(auto v:vec[p]){
		t.merge(v.fi,v.se,p);
		if(v.fi!=s&&v.se!=s)t1.merge(v.fi,v.se,p);
	}
	if(l==r){
		if(e[l].u==s||e[l].v==s)--ct;
		if(!chk()){
			Ans+=1ll*e[l].w;
			ins(1,1,m,l+1,mp(e[l].u,e[l].v));
			if(e[l].u==s||e[l].v==s)--k;
		}
		t.back(p),t1.back(p);
		return;
	}
	solve(ls,l,mid),solve(rs,mid+1,r);
	t.back(p),t1.back(p);
}
int main(){
	scanf("%d%d%d%d",&n,&m,&k,&s);
	for(int i=1;i<=m;++i)scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);
	sort(e+1,e+m+1),reverse(e+1,e+m+1);
	for(int i=1;i<=m;++i){
		if(e[i].v==s)swap(e[i].u,e[i].v);
		if(e[i].u!=s){e1[++tt]=e[i];continue;}
		if(!vis[e[i].v]){++ct;e1[++tt]=e[i],vis[e[i].v]=1;continue;}
	}
	m=tt;for(int i=1;i<=m;++i)e[i]=e1[i];
	t.init(),t1.init(),reverse(e+1,e+m+1);
    for(int i=1;i<=m;++i){
    	t.merge(e[i].u,e[i].v,0);
    	if(e[i].u!=s&&e[i].v!=s)t1.merge(e[i].u,e[i].v,0);
	}
	if(!chk()){puts("nonnondayo");return 0;}
	t.back(0),t1.back(0);
	for(int i=1;i<=m;++i)Ins(1,1,m,i-1,mp(e[i].u,e[i].v));
	solve(1,1,m),cout<<Ans<<endl;
	return 0;
}