Solve the programming task below in a Python markdown code block.
Read problems statements in Mandarin chinese, Russian and Vietnamese as well. 

Masha has $N$ minions. Each minion has two characteristics: power $a$ and endurance $b$. Masha thinks that a non-empty set of minions $\{m_{1}, m_{2}, \dots, m_{k}\}$ with characteristics $(a_{m_{1}},b_{m_{1}}), (a_{m_{2}},b_{m_{2}}), \dots, (a_{m_{k}},b_{m_{k}})$ is *good* if the mean endurance of this set doesn't exceed the minimum power in it, i.e. if $min(a_{m_{1}}, a_{m_{2}}, \dots, a_{m_{k}}) ≥ (b_{m_{1}}+b_{m_{2}}+\dots+b_{m_{k}}) / k$.

Masha would like to choose a good subset of her minions and give these minions to Mark. Your task is to calculate the maximum number of minions Masha can give to Mark.

------  Input ------
The first line of the input contains a single integer $T$ denoting the number of test cases. The description of $T$ test cases follows.
The first line of each test case contains a single integer $N$.
The following $N$ lines describe minions. Each of these lines contains two space-separated integers $a$ and $b$ denoting the power and endurance of one minion.

------  Output ------
For each test case, print a single line containing one number — the size of the largest good set of minions, or $0$ if no such set exists.

------  Constraints  ------
$1 ≤ T ≤ 1,000$
$1 ≤ N ≤ 4\cdot10^{5}$
$1 ≤ a, b ≤ 10^{9}$
the sum of $N$ for all test cases does not exceed $4\cdot10^{5}$

----- Sample Input 1 ------ 
2
3
1 4
3 3
2 1
2
3 5
1 4
----- Sample Output 1 ------ 
2
0
----- explanation 1 ------ 
Example case 1: The set of minions $\{2, 3\}$ is good, since $\mathrm{min}(3,2) ≥ (3+1)/2$.

Example case 2: There is no non-empty good subset of minions.