#include<iostream>
#include<algorithm>
#include<string>
#include<cmath>
#include<cstdlib>
#include<vector>
#include<queue>
using namespace std;

int F[10001][10001];
int main()
{
	freopen("hardest.in","r",stdin);
	freopen("hardest.out","w",stdout);
	int inf=987654321;
	int t,n,m,x,y,z;
	cin>>t;
	for(int i=1;i<=t;i++)
	{
		cin>>n>>m;
		for(int j=1;j<=n;j++)
		{
			for(int k=1;k<=n;k++)
			{
				if(j==k)
					F[j][k]=0;
				else
					F[j][k]=inf;
			}
		}
		for(int j=1;j<=m;j++)
		{
			cin>>x>>y>>z;
			F[x][y]=z;
		}
		for(int j=1;j<=n;j++)
		{
			for(int k=1;k<=n;k++)
			{
				for(int l=1;l<=n;l++)
				{
					if(F[k][l]>F[k][j]+F[j][l])
						F[k][l]=F[k][j]+F[j][l];
				}
			}
		}
		if(F[1][y]!=inf)
			cout<<F[1][y]<<endl;
		else
			cout<<-1<<endl;
	}
	return 0;
}