// This amazing code is by Eric Sunli Chen.
#include<bits/stdc++.h>
using namespace std;
template<typename T> bool get_int(T &x)
{
    char t=getchar();
    bool neg=false;
    x=0;
    for(; (t>'9'||t<'0')&&t!='-'&&t!=EOF; t=getchar());
    if(t=='-')neg=true,t=getchar();if(t==EOF)return false;
    for(; t<='9'&&t>='0'; t=getchar())x=x*10+t-'0';
    if(neg)x=-x;return true;
}
template<typename T> void print_int(T x)
{
    if(x<0)putchar('-'),x=-x;
    short a[20]= {},sz=0;
    while(x>0)a[sz++]=x%10,x/=10;
    if(sz==0)putchar('0');
    for(int i=sz-1; i>=0; i--)putchar('0'+a[i]);
}
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define get1(a) get_int(a)
#define get2(a,b) (get1(a)&&get1(b))
#define get3(a,b,c) (get1(a)&&get2(b,c))
#define printendl(a) print_int(a),puts("")
typedef long long LL;
typedef unsigned long long uLL;
typedef pair<int,int> pii;
const int inf=0x3f3f3f3f;
const LL Linf=1ll<<61;
const double pi=acos(-1.0);

const int mod=998244353;
const int maxn=1111;
vector<int> g[maxn],l[maxn];
int n,m,dist2[maxn];
LL dist[maxn];

int dijkstra(int vx)
{
    memset(dist,-1,(n+3)*sizeof(LL));
    priority_queue<pair<LL,int> >pq;
    pq.push(mp(0,vx));
    dist[vx]=dist2[vx]=0;
    while(!pq.empty())
    {
        int x=pq.top().ss;LL d=-pq.top().ff;pq.pop();
        if(dist[x]!=d)continue;
        int v=dist2[x];if(x!=vx)v=max(v,x);
        for(int i=0;i<(int)g[x].size();i++)
        {
            if(dist[g[x][i]]==-1||dist[g[x][i]]>d+l[x][i])
            {
                dist[g[x][i]]=d+l[x][i];
                dist2[g[x][i]]=v;
                pq.push(mp(-dist[g[x][i]],g[x][i]));
            }
            else if(dist[g[x][i]]==d+l[x][i])dist2[g[x][i]]=min(dist2[g[x][i]],v);
        }
    }
    int ret=0;
    for(int i=1;i<=n;i++)
    {
        ret+=dist2[i];
        if(ret>=mod)ret-=mod;
    }
    return ret;
}

void solve()
{
    get2(n,m);
    for(int i=1;i<=n;i++)
    {
        g[i].clear();
        l[i].clear();
    }
    for(int i=1,u,v,w;i<=m;i++)
    {
        get3(u,v,w);
        g[u].pb(v);g[v].pb(u);l[u].pb(w);l[v].pb(w);
    }
    int ans=0;
    for(int i=1;i<=n;i++)
    {
        ans+=dijkstra(i);
        if(ans>=mod)ans-=mod;
    }
    printf("%d\n",ans);
}

int main()
{
    int tc;get1(tc);
    while(tc--)solve();
    return 0;
}