#include<bits/stdc++.h>
#define pii pair<int,int>
#define fi first
#define se second
#define ll long long
#define pb push_back
using namespace std;
bool vis[50004];
struct Node{int u,v,w;}e[500004];
bool operator<(Node a,Node b){return a.w<b.w;}
int n,m,s,k,W[50004],To[50004],tot,sz[50004],ct[50040],fa[50004],Ct,ct0;
vector<pii>vec[200005];
pii stk[1000005];
int col[1000005],tail,ctk,res[50004];
int find(int r){
	if(r==fa[r])return r;
	return find(fa[r]);
}
void merge(int u,int v){
	u=find(u),v=find(v);if(u==v)return;
	ct0-=(!ct[u])+(!ct[v]),--Ct;
	if(sz[u]<sz[v])swap(u,v);fa[v]=u;
	sz[u]+=sz[v],ct[u]+=ct[v];
    ct0+=(!ct[u]);
}
void Merge(int u,int v,int t){
	u=find(u),v=find(v);if(u==v)return;
	ct0-=(!ct[u])+(!ct[v]),--Ct;
	if(sz[u]<sz[v])swap(u,v);fa[v]=u;
	stk[++tail]=make_pair(u,v),col[tail]=t;
    sz[u]+=sz[v],ct[u]+=ct[v];
    ct0+=(!ct[u]);
}
void rollback(int p){
	while(tail&&col[tail]==p){
		int u=stk[tail].fi,v=stk[tail].se;
		ct0-=(!ct[u]),++Ct;
		sz[u]-=sz[v],ct[u]-=ct[v],fa[v]=v;
		ct0+=(!ct[u])+(!ct[v]);--tail;
	}
}
#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 solve(int p,int l,int r){
	for(auto v:vec[p])Merge(v.fi,v.se,p);
	if(l==r){
		if(ctk==k){rollback(p);return;}Merge(s,To[l],p+1);
		if(!ct0&&k-ctk-1>=Ct-1){res[l]=1,++ctk,rollback(p+1),rollback(p),ins(1,1,tot,l+1,make_pair(s,To[l]));return;}
		rollback(p+1),rollback(p);return;
	}
	solve(ls,l,mid),solve(rs,mid+1,r),rollback(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);
		if(e[i].u==s)ct[e[i].v]=1;
		if(e[i].v==s)ct[e[i].u]=1;
	}ct[s]=1;
	sort(e+1,e+m+1);
	for(int i=1;i<=n;++i)sz[i]=1,fa[i]=i,ct0+=(!ct[i]);Ct=n;
	for(int i=1;i<=m;++i){
		if(e[i].v==s)swap(e[i].v,e[i].u);
		if(e[i].u==s){
			if(vis[e[i].v])continue;
			vis[e[i].v]=1;To[++tot]=e[i].v,W[tot]=e[i].w;
		}else merge(e[i].u,e[i].v);
	}
	if(k>tot){puts("nonnondayo");return 0;}
	solve(1,1,tot);
	if(ctk<k){puts("nonnondayo");return 0;}
	int Mx=0;ll Ans=0;
	for(int i=1;i<=n;++i)sz[i]=1,fa[i]=i,ct[i]=1;Ct=n,ct0=0;
	for(int i=1;i<=tot;++i)if(res[i])Mx=W[i],Ans+=1ll*W[i],merge(s,To[i]);
	for(int i=1;i<=m;++i){
		if(e[i].u==s)continue;
		if(e[i].w<Mx||Ct>1)Ans+=1ll*e[i].w,merge(e[i].u,e[i].v);
	}cout<<Ans;
	return 0;
}