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=[int(x) for x in raw_input().split()]
s=0
for i in xrange(1,((n-1)/a)+1):
    s+=(a*i)
for j in xrange(1,((n-1)/b)+1):
    s+=(b*j)
for k in xrange(1,((n-1)/(a*b))+1):
    s-=((a*b)*k)
print s