#include<iostream>
#include<vector>
#include<map>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<queue>
#include<fstream>
#include<sstream>
#include<stack>
#include<list>
#include<deque>
#include<bitset>
#include<utility>
#include<climits>
#include<iomanip>
#include<ctime>
#include<complex>
using namespace std;


#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)

#define inf INT_MAX/3
#define pb push_back
#define mp make_pair
#define all(a) (a).begin(),(a).end()
#define SET(a,c) memset(a,c,sizeof a)
#define CLR(a) memset(a,0,sizeof a)
#define pii pair<int,int>
#define pcc pair<char,char>
#define pic pair<int,char>
#define pci pair<char,int>
#define VS vector<string>
#define VI vector<int>
#define debug(x) cout<<#x<<": "<<x<<endl
#define MIN(a,b) (a>b?b:a)
#define MAX(a,b) (a>b?a:b)
#define pi 2*acos(0.0)
#define INFILE() freopen("in0.txt","r",stdin)
#define OUTFILE()freopen("out0.txt","w",stdout)
#define in scanf
#define out printf
#define ll unsigned long long



#define Mx 100015
string str;

ll len;
ll tree[4*Mx];

void insert(int cur , int st , int ed , int pos)
{
    if(st==ed && st==pos)
    {
        tree[cur]++;
        return ;
    }

    int mid,lft,rgt;
    mid=(st+ed)/2;
    lft=2*cur;
    rgt=lft+1;

    if(pos<=mid)
    {
        insert(lft,st,mid,pos);
    }
    else insert(rgt,mid+1,ed,pos);

    tree[cur]=tree[lft]+tree[rgt];
}

int query(int cur , int st , int ed , int x , int y)
{
    if(x>y)return 0;

    if(st==x && ed==y)
    {
        return tree[cur];
    }
    int mid,lft,rgt;
    mid=(st+ed)/2;
    lft=2*cur;
    rgt=lft+1;

    if(y<=mid)return query(lft,st,mid,x,y);
    else if(x>mid)return query(rgt,mid+1,ed,x,y);
    else
    {
        int a=query(lft,st,mid,x,mid);
        int b=query(rgt,mid+1,ed,mid+1,y);
        return a+b;
    }

}


int main()
{

    int i,j,k;
    int cas,ks;
    cin>>ks;
    FOR(cas,1,ks+1)
    {
        cin>>len;
        int nn=(4*len)+5;
        //SET(tree,0);
        FOR(i,0,nn)tree[i]=0;
        cin>>str;

//        scanf("%s",str);
        int high=0;


        ll sz=0;
        ll con=0;
        ll res=0;

        for(i=0; i<len; i++)
        {
            if(str[i]=='4')
            {
                con=1;
                sz=sz+1;

            }
            else if(str[i]=='7')
            {

                if(sz==0)
                {
                    con=1;
                }
                else
                {
                    ll bad=0;
                    bad=query(1,1,len,1,con-1 );


                    res=res+( i - (2*bad) );


                    insert(1,1,len,con);
                    con++;
                    sz=sz-1;
                }
            }
        }
        cout<<res<<endl;

    }

    return 0;
}
/*
2
4
4747
10
4447477747

4447774747444777


  2
  4
  4747
  10
  4447477747


*/