For two positive integers 'a' & 'b' if (a+b)^a+b is divisivble by 500 then what is the least possible value of 'a' * 'b' .

I think the smallest "a and b" would be:

a = 1 and b=9, [1 + 9]^(1+9) =10^10 mod 500 =0

So, a x b =1 x 9 =9 - the least possible value of (a*b)

thnx for the help the answer is correct .