After 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 <image> equals 0.

As usual, Alyona has some troubles and asks you to help.

Input

The only line of the input contains two integers n and m (1 ≤ n, m ≤ 1 000 000).

Output

Print 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.

Examples

Input

6 12


Output

14


Input

11 14


Output

31


Input

1 5


Output

1


Input

3 8


Output

5


Input

5 7


Output

7


Input

21 21


Output

88

Note

Following 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.
#!/usr/bin/python

import os
import sys
import itertools

def solve(f):
    x, y = f.read_int_list()
    xl = [x/5] * 5
    yl = [y/5] * 5
    xl[0] -= 1
    yl[0] -= 1
    for i in xrange(5):
        if x%5 > i-1: xl[i] += 1
        if y%5 > i-1: yl[i] += 1

    ans = 0
    for i in xrange(5):
        ans += xl[i]*yl[(5-i)%5]

    return ans

class Reader(object):
    def __init__(self, filename=None):
        self.test_mode = filename is not None
        self.cases = 1
        self.buffer = []
        if self.test_mode:
            with open(filename) as f:
                blank_flg = False
                for line in f:
                    line = line.strip()
                    if line:
                        self.buffer.append(line)
                        blank_flg = False
                    else:
                        if not blank_flg: self.cases += 1
                        blank_flg = True

    def __readline(self):
        return self.buffer.pop(0) if self.test_mode else raw_input()

    def read_int(self):
        return int(self.__readline())
    def read_float(self):
        return float(self.__readline())
    def read_long(self):
        return long(self.__readline())
    def read_str(self):
        return self.__readline()

    def read_int_list(self):
        return [int(item) for item in self.__readline().split()]
    def read_float_list(self):
        return [float(item) for item in self.__readline().split()]
    def read_long_list(self):
        return [long(item) for item in self.__readline().split()]
    def read_str_list(self):
        return self.__readline().split()

if __name__ == '__main__':
    filename = sys.argv[1] if len(sys.argv)>1 else None
    f = Reader(filename)
    if f.test_mode:
        for c in xrange(f.cases):
            print "Case #%d"%(c+1)
            print solve(f)
    else:
        print solve(f)
