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:
n,a,b= map(int, raw_input().split())
aDivs = (n-1)/a
bDivs = (n-1)/b
abDivs = (n-1)/(a*b)
aDivsSum = a*aDivs*(aDivs+1)/2
bDivsSum = b*bDivs*(bDivs+1)/2
abDivsSum = a*b*abDivs*(abDivs+1)/2
print aDivsSum + bDivsSum-abDivsSum