#include <stdio.h>
int main()
{
	freopen("oz.in","r",stdin);
	freopen("oz.out","w",stdout);
	int n,m,i,j,d,r;
	scanf("%d%d",&n,&m);
	for (r=1; r<=m; r++)
		scanf("%d%d%d",&i,&j,&d);
	printf("-1");
	return 0;
}