#include <cstring>
#include <cmath>
#include <cstdio>
#include <climits>
#include <ctime>
#include <cassert>
#include <cctype>
#include <iostream>
#include <algorithm>
#include <numeric>
#include <map>
#include <set>
#include <queue>
#include <string>
#include <vector>
#include <bitset>
#include <utility>

#define all(x) (x).begin(), (x).end()
#define bit(x) (1 << (x))
#define cnt1(x) (__builtin_popcount(x))
#define LET(it,v) __typeof(v) it(v)
#define mset0(x) memset((x), 0, sizeof((x)))
#define mset1(x) memset((x), -1, sizeof((x)))
#define pb push_back
#define PQ priority_queue
#define REP(it,v) for(LET(it,v.begin());it!=v.end();it++)
#define sqr(x) ((x) * (x))
#define sz(x) ((int)(x.size()))
#define X first
#define Y second

using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
typedef pair<LL, LL> pll;
typedef vector<int> vi;
typedef vector<pii> vpii;

template <class T> inline void chkmin(T &a, T b) {
    if (b < a) a = b;
}
template <class T> inline void chkmax(T &a, T b) {
    if (a < b) a = b;
}

const int MX = 100005;
int cnt[MX], w[MX];
LL C3(LL n) {
    return n * (n - 1) * (n - 2) / 6;
}

int main() {
    
    int T, n, m;
    int i;
    
    for (scanf("%d", &T); T--; ) {
        scanf("%d%d", &n, &m);
        
        for (i = 1; i <= n; i++) scanf("%d", w + i);
        for (i = 0; i <= n + 1; i++) cnt[i] = 0;
        
        int l, r;
        for (i = 1; i <= m; i++) {
            scanf("%d%d", &l, &r);
            cnt[l]++, cnt[r + 1]--;
        }
            
        if (m < 3) {
            puts("0");
            continue;
        }
        
        LL ans = 0;
        for (i = 1; i <= n; i++) {
            cnt[i] += cnt[i - 1];
            ans += w[i] * C3(cnt[i]);
        }
        
        LL tot = C3(m);
        LL tp = __gcd(tot, ans);
        ans /= tp, tot /= tp;
        
        if (tot == 1) printf("%lld\n", ans);
        else printf("%lld/%lld\n", ans, tot);
    }
    
    return 0;
}