#include <iostream>

#include <cstring>

#include <stack>

#include <cstdio>

#include <cmath>

#include <queue>

#include <algorithm>

#include <vector>

#include <set>

#include <map>

const double eps=1e-8;

const double PI=acos(-1.0);

using namespace std;

int re[100005];

int main()

{

int n,m;

while(~scanf("%d %d",&n,&m)){

memset(re,0,sizeof(re));

int u,v,w;

for(int i=0;i<m;i++){

scanf("%d%d%d",&u,&v,&w);

if(u!=v){

re[u]+=w;

re[v]+=w;

}

}

sort(re+1,re+n+1);

cout<<re[1]<<endl;

}

return 0;

}