) and 19. Write down a correspondence between the positive natural numbers N+-1,2,3. o1kand are odd positive integersthe collection of all finite strings s of O's and 1's where s is an odd number of O's followed by an odd number of 1's. For this problem you can be a bit informal and indicate the correspondence f by ordering the binary string in the set and letting f(1) = the first element in the ordered set, f(2) = the 2nd element in the ordered set, etc