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:
""" Created by : Rahul Johari
				 Thapar University """

#a = map(int,raw_input.split())
#sys.stdin.readline()
import sys
n,a,b = map(int,sys.stdin.readline().split())
su = 0
for num in range(n):
	if num % a == 0 or num % b == 0:
		su = su + num
print su