#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
int sum[3005], ufs[3005];
int Find(int x)
{
    if(ufs[x]==0)
        return x;
    return ufs[x] = Find(ufs[x]);
}
int main(void)
{
    int n, m, i, x, y, z, cnt, t1, t2;
    while(scanf("%d%d", &n, &m)!=EOF)
    {
        cnt = n-1;
        memset(ufs, 0, sizeof(ufs));
        memset(sum, 0, sizeof(sum));
        for(i=1;i<=m;i++)
        {
            scanf("%d%d%d", &x, &y, &z);
            if(x==y)
                continue;
            sum[x] += z;
            sum[y] += z;
            t1 = Find(x);
            t2 = Find(y);
            if(t1!=t2)
            {
                ufs[t1] = t2;
                cnt--;
            }
        }
        if(cnt==0)
        {
            sort(sum+1, sum+n+1);
            printf("%d\n", sum[1]);
        }
        else
            printf("0\n");
    }
    return 0;
}