#include <cstdio>
#include <iostream>
#include <string>
#include <sstream>
#include <cstring>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <map>
#define PI acos(-1.0)
#define ms(a) memset(a,0,sizeof(a))
#define msp memset(mp,0,sizeof(mp))
#define msv memset(vis,0,sizeof(vis))
using namespace std;
//#define LOCAL
struct Node
{
    int b;
    int e;
}t;
int cmp(Node a,Node b)
{
    if(a.b==b.b)return a.e<b.e;
    return a.b<b.b;
}
vector<Node> v;
int main()
{
#ifdef LOCAL
    freopen("in.txt", "r", stdin);
#endif // LOCAL
    ios::sync_with_stdio(false);
    int N;
    cin>>N;
    while(N--)
    {
        int n;
        cin>>n;
        v.clear();
        while(n--)
        {cin>>t.b>>t.e;
        if(t.e<t.b)swap(t.e,t.b);
        v.push_back(t);}
        sort(v.begin(),v.end(),cmp);
        int ans=0;
        while(v.size())
        {
            t=v[0],ans++,v.erase(v.begin());
            for(int i=0;i<(int)v.size();i++)
            {
                if(v[i].b<=t.e)continue;//不好描述，算了
                if((t.e+1)%2==0&&v[i].b-1==t.e)continue;//奇数房的对面房间
                else t.e=v[i].e,v.erase(v.begin()+i),i--;//原来上一句是没有的，WA
            }
        }
        printf("%d\n",ans*10);
    }
    return 0;
}