In this HackerEarth The exam problem solution Kate is wizard. Now she should pass the exam.

During the exam she have to go into the magic room N times. Initially there are X magic items in the room. Before each visit she can use magic to decrease the number of magic items in the room. For each item she spends 1 mana point to destroy it. After each visit the number of magic items increases by 2 times. She can't go into room if there are more than L magic items in it. What minimum mana points does Kate need to pass the exam?

You need to solve this problem for several test cases.

## HackerEarth The exam problem solution.

`def solve():    x, l, n = map(int, input().split())    min_erased = -1    max_erased = x    while max_erased - min_erased > 1:        erased = (min_erased + max_erased) // 2        cur_x = x - erased        good = True        for it in range(n):            if cur_x > l:                good = False                break            cur_x *= 2        if good:            max_erased = erased        else:            min_erased = erased    print(max_erased)def main():    t = int(input())    for i in range(t):        solve()main()`