Given three integers n, a, and b, return the nth magical number.
n
a
b
th
A magical number is defined as a positive integer that is divisible by either a or b.
As the result may be very large, return it modulo 109+710^9+7109+7.
Constraints:
1≤1 \leq1≤ n ≤109\leq 10^9≤109
2≤2 \leq2≤ a, b ≤4×104\leq 4 \times 10^4≤4 ...