In Geekland, there lives a very rich girl Siri. For her undergraduation studies she joins an engineering college GIT, Geekland Institute of Technology. The college has a semester wise system, a semester being of K days. Before her first day for the college Siri and her mom went to market for shopping and bought N dresses. Her mom told her that every M^{th} day she will bring her a new dress, but since the shops in the Geekland are open only in the evening, so Siri could only wear her new dress the next day. If on a particular day Siri didn't had a new dress to wear, she bunks that day off the college. Help Siri to know for how many days she will bunk her classes in a semester of K days. 
Example 1:
Input: N = 9, M = 3, K = 15
Output: 
2
Explanation: For first 9 days Siri has new  
dresses and she will wear them for 9 days, 
during these 9 days she will get 3 more dresses
so she will wear them on 10^{th}, 11^{th} and 12^{th} day.
On 12^{th} day she will get one more new dress to 
wear on 13^{th} day. On 15^{th} day she will get one 
more new dress but she can't wear it before 16^{th}
day. For 14^{th} and 15^{th} day she does not have any
new dress, so she will bunk two days.
Example 2:
Input: N = 2, M = 2, K = 10
Output: 
4
Your Task:  
You dont need to read input or print anything. Complete the function bunkDays() which takes integers N, M and K as input parameters and returns the number of days Siri will bunk her classes.
Expected Time Complexity: O(1)
Expected Auxiliary Space: O(1)
Constraints:
1 ≤ N, M, K ≤ 1000

Source: geeksforgeeks | Difficulty: EASY
Tags: Mathematics

Starter code: #User function Template for python3
class Solution:
	def bunkDays(self, N, M, K):
		# code here


Solutions:
class Solution:

	def bunkDays(self, N, M, K):
		s = (K - 1) // M + N
		if s >= K:
			return 0
		else:
			return K - s


class Solution:

	def bunkDays(self, N, M, K):
		a1 = K - M
		a1 = (a1 + M - 1) // M
		a1 += N
		a1 = min(a1, K)
		return K - a1