#include<iostream>
#include<algorithm>
#include<string.h>
#include<string>
#include<stdio.h>
#include<math.h>
#include<stack>
#include<queue>
#include<map>
#include<hash_map>
#include<vector>
#include<set>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
#define mem(a,num) memset(a,num,sizeof(a))
#define inf(a,n) fill(a,a+n,0x3f3f3f3f)


int main()
{
    int n,m,x,y,c;
    ll cnt[3050];
    while(scanf("%d%d",&n,&m)!=EOF){
        mem(cnt,0);
        for(int i=0;i<m;++i){
            scanf("%d%d%d",&x,&y,&c); if(x==y)continue;
            cnt[x]+=c;
            cnt[y]+=c;
        }
        ll ans=1e18;
        for(int i=1;i<=n;++i)ans=min(ans,cnt[i]);
        cout<<ans<<endl;
    }
    return 0;
}