A. Alyona and Numberstime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputAfter finishing eating her bun, Alyona came up with two integers n and m. She decided to write down two columns of integers — the first column containing integers from 1 to n and the second containing integers from 1 to m. Now the girl wants to count how many pairs of integers she can choose, one from the first column and the other from the second column, such that their sum is divisible by 5.Formally, Alyona wants to count the number of pairs of integers (x, y) such that 1 ≤ x ≤ n, 1 ≤ y ≤ m and  equals 0.As usual, Alyona has some troubles and asks you to help.InputThe only line of the input contains two integers n and m (1 ≤ n, m ≤ 1 000 000).OutputPrint the only integer — the number of pairs of integers (x, y) such that 1 ≤ x ≤ n, 1 ≤ y ≤ m and (x + y) is divisible by 5.ExamplesInput6 12Output14Input11 14Output31Input1 5Output1Input3 8Output5Input5 7Output7Input21 21Output88NoteFollowing pairs are suitable in the first sample case:   for x = 1 fits y equal to 4 or 9;  for x = 2 fits y equal to 3 or 8;  for x = 3 fits y equal to 2, 7 or 12;  for x = 4 fits y equal to 1, 6 or 11;  for x = 5 fits y equal to 5 or 10;  for x = 6 fits y equal to 4 or 9. Only the pair (1, 4) is suitable in the third sample case.
Input6 12
Output14
['constructive algorithms', 'math', 'number theory', '*1100']