Jagjit Singh (Jaggi) is among the few fastest athletes of Thapar. Just before the Thapar Olympics he thought of a new way to practice. He decided he will run in intervals. In each interval , he will run at a particular speed. You have to calculate the total distance traveled by him, given the speed M and time S for each interval.

Input
 The first line of the input contains an integer T denoting the number of test cases. The description of T test cases follows. 

Each test case will contain a single number N, the number of intervals. Then N lines follow.
Each of the next N lines will contain the length of the interval in seconds (S) and speed (M) in that interval in(m/sec).


Output

For each test case output the total distance covered by him in meters(m) separated by new line.


Constraints

 0 < T < 100
 0 < N <= 10000
 0 <= S <= 10^5
 0 <= M <= 10^5

 Don't get shocked after looking at constraints, sometimes he becomes super fast. ;) 

Example
Input:
2
3
2 5
1 6
3 10
5
1 1
2 2
3 3
4 10
5 1

Output:
46
59
import sys
t=sys.stdin.readline()
t=int(t)
for k in range(0,t):
	n=sys.stdin.readline()
	n=int(n)
	d=0
	for i in range(0,n):
		string=sys.stdin.readline()
		t,s=string.split(" ")
		t=int(t)
		s=int(s)
		d=d+t*s
	print d