/*
* @Author: NanoApe
* @Date:   2016-07-20 22:18:25
* @Last Modified by:   admin
* @Last Modified time: 2019-08-24 16:09:51
*/

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <vector>

using namespace std;

#define rep(i, l, r) for(int i=l; i<=r; i++)
#define dow(i, l, r) for(int i=l; i>=r; i--)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define clr(x, c) memset(x,c,sizeof(x))

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> Pii;

inline int read()
{
    int x=0,f=0; char ch=getchar();
    while (ch<'0' || '9'<ch) f|=ch=='-', ch=getchar();
    while ('0'<=ch && ch<='9') x=x*10+ch-'0', ch=getchar();
    return f?-x:x;
}

#define Q 998244353
#define maxn 1009

ll f[maxn][maxn];
int q[maxn][maxn];

int main()
{
    int T = read();
    while (T--) {
        int n = read(), m = read();
        rep(i, 1, n) rep(j, 1, n) f[i][j] = i==j?0:1000000000000000LL, q[i][j] = 0;
        ll ans = 0;
        rep(i, 1, m) {
            int x=read(), y=read(), z=read();
            f[x][y] = min(f[x][y], (ll)z);
            f[y][x] = min(f[y][x], (ll)z);
        }
        rep(o, 1, n) rep(i, 1, n) if (f[i][o] != 1000000000000000LL) rep(j, 1, n) {
            if (f[i][o]+f[o][j] < f[i][j]) {
                f[i][j] = f[i][o]+f[o][j];
                ans += o-q[i][j];
                q[i][j] = o;
            }
        }
        printf("%d\n", ans%Q);
    }
    return 0;
}