#include<iostream>

#include<algorithm>

#include<cstring>

using namespace std;

int num[1005];

int main()

{

    int t;

    cin>>t;

    while(t--)

    {

        int n;

        cin>>n;

        int maxn=0;

        memset(num,0,sizeof(num));

        for(int i=0; i<n; i++)

        {

            int x,y;

            cin>>x>>y;

            if(x>y)

                swap(x,y);

            if(x%2==1)

                x++;

            if(y%2==1)

                y++;

            for(int i=x; i<=y; i++)

            {

                num[i]++;

                maxn=max(maxn,num[i]);

            }

        }

        cout<<maxn*10<<endl;

    }

}