没分求调

#include<bits/stdc++.h>
using namespace std;
int n,m;
int a[20010];
struct node{
	int x,y,zhi;
}b[20101];

int cha(int x){
	if(a[x]!=x)return a[x]=cha(a[x]);
	else return x;
}
int bing(int x,int y){
	int fx = cha(x);
	int fy = cha(y);
	if(fx != fy){
		a[fx] = fy;
	}
}
bool cmp(node x,node y){
	return x.zhi>y.zhi;
}
int main(){
	cin>>n>>m;
	for(int i=1;i<=2*n;i++){
		a[i]=i;
	}
	for(int i=1;i<=m;i++){
		int x,y;
		cin>>b[i].x>>b[i].y>>b[i].zhi;
	}
	sort(b+1,b+1+m,cmp);
	for(int i=1;i<=m;i++){
		bing(b[i].x,b[i].y+n);
		bing(b[i].y,b[i].x+n);
		if(cha(b[i].x)==cha(b[i].x+n)||cha(b[i].y)==cha(b[i].y+n)){
			cout<<b[i].zhi;
			return 0;
		}
	}
	cout<<0;
	return 0;
}