#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int flag[200005],a[200005];
int n,m;
int T;
long long ans1,ans2;
int w[200005];
long long gcd(long long x,long long y)
{
    if(y==0)return x;
    return gcd(y,x%y);
}
void down(int x)
{
    if(flag[x]==0)return;
    flag[x*2]+=flag[x];
    flag[x*2+1]+=flag[x];
    flag[x]=0;
}
void modify(int x,int l,int r,int tx,int ty)
{
    if(l>=tx && r<=ty)
    {
        flag[x]++;
        return;
    }
    down(x);
    int mid=(l+r)/2;
    if(mid>=tx)modify(x*2,l,mid,tx,ty);
    if(mid<ty)modify(x*2+1,mid+1,r,tx,ty);
}
int query(int x,int l,int r,int wh)
{
    if(l==r && l==wh)return flag[x];
    down(x);
    int mid=(l+r)/2;
    if(mid>=wh)return query(x*2,l,mid,wh);
    else return query(x*2+1,mid+1,r,wh);
}
int main()
{
    scanf("%d",&T);
    while(T--)
    {
        memset(flag,0,sizeof(flag));
        memset(a,0,sizeof(a));
        scanf("%d%d",&n,&m);
        for(int i=1;i<=n;i++)scanf("%d",&w[i]);
        for(int i=1;i<=m;i++)
        {
            int x,y;
            scanf("%d%d",&x,&y);
            modify(1,1,n,x,y);
        }
        ans1=0;
        ans2=(long long)m*(m-1)*(m-2)/6;
        for(int i=1;i<=n;i++)
        {
            int p=query(1,1,n,i);
            if(p<3)continue;
            long long tt=(long long)p*(p-1)*(p-2)/6;
            ans1+=tt*w[i];
        }
        if(ans1==0 || ans2==0)
        {
            puts("0");
            continue;
        }
        long long ttt=gcd(ans2,ans1);
        ans1/=ttt;
        ans2/=ttt;
        if(ans2!=1)printf("%I64d/%I64d\n",ans1,ans2);else printf("%I64d\n",ans1);
    }
    return 0;
}