//#pragma comment(linker,"/STACK:102400000,102400000")
#include<stdio.h>
#include<iostream>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<string>
#define ll long long
#define db double
#define PB push_back
#define lson k<<1
#define rson k<<1|1
using namespace std;

const int N = 50005;

int w[N], cnt[N];

ll gcd(ll a, ll b)
{
    if(a > b) swap(a, b);
    while(a)
    {
        ll t = a;
        a = b % a;
        b = t;
    }
    return b;
}

int main()
{
#ifdef PKWV
//    freopen("in.in","r",stdin);
#endif // PKWV
    int T;
    scanf("%d", &T);
    while(T--)
    {
        int n, m;
        scanf("%d%d", &n, &m);
        for(int i = 1; i <= n; i++) scanf("%d", &w[i]), cnt[i] = 0;
        for(int i = 0; i < m; i++)
        {
            int l, r;
            scanf("%d%d", &l, &r);
            cnt[l]++, cnt[r + 1]--;
        }
        int num(0);
        ll tol(0LL);
        for(int i = 1; i <= n; i++)
        {
            num += cnt[i];
            if(num >= 3)
            {
                tol += (ll)w[i] * (ll)num * (ll)(num - 1) * (ll)(num - 2) / 6LL;
            }
        }
        ll fm = 1LL;
        if(m >= 3) fm *= (ll)m * (ll)(m - 1) * (ll)(m - 2) / 6LL;
        ll g = gcd(tol, fm);
        tol /= g, fm /= g;
        if(fm == 1) printf("%I64d\n", tol);
        else printf("%I64d/%I64d\n", tol, fm);
    }
    return 0;
}