# -*- coding: cp1252 -*-
""" Problem SPOJ 1025: Fashion shows: Mix hottest couples (FASHION) """
import sys
# import psyco
# psyco.full()
    
def init_testcase():
    cases = [
            '2',
            '2',
            '1 1',
            '3 2',
            '3',
            '2 3 2',
            '1 3 2',
            ]
    return cases
 
def hotsum (params):
    # print params
    men = map(int, params[0])
    women = map(int, params[1])
    men.sort()
    women.sort()
    result = 0
    for m, w in zip (men, women):
        result += m * w
    return result
        
    
def split_it(s):
    return s.split()
    
def main():
    testflag = 0
    if testflag:
        cases = []
        cases.extend(init_testcase())
        cases.append('') # dummy to cope with suppression of last line when reading from stdin
        print cases
    else:
        cases = sys.stdin.read().split('\n')
    
    results = []
    for line in zip(*[iter(cases[1:-1])]*3):
        # print 'line', line
        if line:
            result = hotsum(map(split_it, line[1:]))
            results.append(str(result))
    sys.stdout.writelines ('\n'.join(results))
    sys.stdout.write('\n')
    

if __name__ == '__main__':
    main()