#include <map>
#include <set>
#include <list>
#include <queue>
#include <deque>
#include <cmath>
#include <stack>
#include <vector>
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
#define endl '\n'
#define PI acos(-1)
#define PB push_back
#define ll long long
#define INF 0x3f3f3f3f
#define mod 1000000007
#define pll pair<ll, ll>
#define lowbit(abcd) (abcd & (-abcd))
#define max(a, b) ((a > b) ? (a) : (b))
#define min(a, b) ((a < b) ? (a) : (b))

#define IOS                      \
    ios::sync_with_stdio(false); \
    cin.tie(0);                  \
    cout.tie(0);
#define FRE                              \
    {                                    \
        freopen("in.txt", "r", stdin);   \
        freopen("out.txt", "w", stdout); \
    }

inline ll read()
{
    ll x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        x = (x << 1) + (x << 3) + (ch ^ 48);
        ch = getchar();
    }
    return x * f;
}
//==============================================================================

ll fa[3010];
ll sum[3010], n, m;
void init()
{
    for (int i = 1; i <= n; i++)
        fa[i] = i;
    fill(sum, sum + 3001, 0);
}
ll find(ll x)
{
    if (fa[x] == x)
        return x;
    return fa[x] = find(fa[x]);
}
void mix(ll a, ll b)
{
    ll fa1 = find(a), fb1 = find(b);
    if (fa1 != fb1)
        fa[fa1] = fb1;
}
int main()
{
    while (cin >> n >> m)
    {
        init();
        ll u, v, w;
        for (int i = 1; i <= m; i++)
        {
            cin >> u >> v >> w;
            if (u == v)
                continue;
            sum[v] += w,
                sum[u] += w;
            mix(u, v);
        }
        ll flag = 0;
        for (int i = 1; i <= n; i++)
            if (find(i) == i)
                flag++;
        if (flag > 1)
            cout << 0 << endl;
        else
        {
            ll ans = INF;
            for (int i = 1; i <= n; i++)
                ans = min(ans, sum[i]);
            cout << ans << endl;
        }
    }

    return 0;
}