#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
#include <vector>
#include <queue>
#include <iostream>
#include <cassert>
#include <bitset>
#include <ctime>

using namespace std;

typedef long long LL;
typedef double DB;
typedef pair<int, int> PII;
typedef vector<int> VI;

#define X first
#define Y second
#define pb push_back

template<class T>
inline void chkmin(T &x, T y) {
    if (y < x) x = y;
}

template<class T>
inline void chkmax(T &x, T y) {
    if (x < y) x = y;
}


const int MN = 50005;
int n, val[MN], m;
int l[MN], r[MN], w[MN];
VI V[MN];

inline void add(int x) {
    for (; x <= n; x += x & -x) val[x]++;    
}

inline int get(int x, int y) {
    int rlt = 0;
    x--;
    for (; x; x -= x & -x) rlt -= val[x];
    for (; y; y -= y & -y) rlt += val[y];
    return rlt;    
}

int main() {
    
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
    
    int i, j, k, tn;
    
    for (scanf("%d", &tn); tn--; ) {
        scanf("%d%d", &n, &m);
        for (i = 1; i <= n; i++) V[i].clear();
        for (i = 1; i <= n; i++) scanf("%d", w + i);
        for (i = 0; i < m; i++) {
            scanf("%d%d", l + i, r + i);
            V[l[i]].pb(r[i]);
        }
        if (m <= 2) {
            printf("0\n");
            continue;    
        }
        memset(val, 0, sizeof val);
        LL ans = 0;
        for (i = 1; i <= n; i++) {
            for (j = V[i].size() - 1; j >= 0; j--) {
                add(V[i][j]);    
            }
            int t = get(i, n);
            if (t >= 3) {
                ans += 1LL * w[i] * t * (t - 1) * (t - 2) / 6;
            }
        }
        LL b = 1LL * m * (m - 1) * (m - 2) / 6;
        LL g = __gcd(ans, b);
        if (b == g) {
            printf("%lld\n", ans / g);    
        } else {
            printf("%lld/%lld\n", ans / g, b / g);
        }
    }
    
    return 0;    
}