#include <bits/stdc++.h>
using namespace std;
#define int long long
int T,ans=1e18,n,m;
struct aaaa{
	int u,t;
	bool operator <(const aaaa &a)const{
		return t<a.t;
	}
	bool operator >(const aaaa &a)const{
		return t>a.t;
	}
};
vector<int>v[2010];
int d[2010][2010];
int dis[2010],mp[2010];
priority_queue<aaaa,vector<aaaa>,greater<aaaa> >q;
void dij(int st){
	while(!q.empty())q.pop();
	for(int x=1;x<=n;x++){
		dis[x]=1e15;mp[x]=0;
	}
	dis[st]=0;
	q.push({st,0});
	while(!q.empty()){
		aaaa sx=q.top();
		q.pop();
		if(mp[sx.u]==1)continue;
		mp[sx.u]=1;
		for(auto y:v[sx.u]){
			if(d[sx.u][y]==0)continue;
			int val=d[sx.u][y];
			if(dis[sx.u]+val<dis[y]){
				dis[y]=dis[sx.u]+val;
				q.push({y,dis[y]});
			}
		}
	}
}
signed main(){
	cin>>T;
	cin>>n>>m;
	for(int x=1;x<=m;x++){
		int u,w,t;
		cin>>u>>w>>t;
		if(T==0){
			d[u][w]=d[w][u]=t;
			v[u].push_back(w);
			v[w].push_back(u);
		}
		else{
			v[u].push_back(w);
			d[u][w]=t;
		}
	}
	for(int x=1;x<=n;x++){
		for(int y=1;y<=n;y++){
			if(d[x][y]!=0){
				int p=d[y][x],qq=d[x][y];
				d[y][x]=d[x][y]=0;
				dij(y);
				ans=min(ans,dis[x]+qq);
				d[y][x]=p,d[x][y]=qq;
			}
		}
	}
	cout<<ans<<endl;
}