Problem: Given three positive integers N, A and B (A < B < N), find the sum of all positive integers less than N, which are divisible by either A or B.

For example, when N = 20, A = 4 and B = 7, the possible values are 4, 7, 8, 12, 14, and 16. Their sum is 61.
Input Format
The only line of the input file contains three space separated integers N, A and B.

Output Format
Output the required sum.

Constraints
10 ≤ N ≤ 50000
2 ≤ A < B < N

SAMPLE INPUT
20 4 7

SAMPLE OUTPUT
61

Solution (in PYTHON):

Solution:
if __name__=="__main__":
	N, A, B = [int(i) for i in raw_input().split()]
	ca=(N-1)/A
	cb=(N-1)/B
	cab = (N-1)/(A*B)
	print ((ca)*(ca+1)*A)/2 + ((cb)*(cb+1)*B)/2 +  - ((cab)*(cab+1)*A*B)/2  #((N-1)/(A*B))*A*B