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 $(x + y) \operatorname{mod} 5$ 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.

Difficulty: interview

Starter code:

Solutions:
ct=0
a, b = list(map(int, input().split(' ')))
x=[0]*5
for i in range(1, b+1):
    x[i%5]+=1
for i in range(1, a+1):
    ct+=x[(0-i)%5]
print(ct)


#!/usr/bin/env python3

try:
    while True:
        n, m = list(map(int, input().split()))
        a = [0] * 5
        b = [0] * 5
        for i in range(1, n + 1):
            a[i % 5] += 1
        for j in range(1, m + 1):
            b[j % 5] += 1

        print(a[0] * b[0] + a[1] * b[4] + a[2] * b[3] + a[3] * b[2] + a[4] * b[1])

except EOFError:
    pass


n, m = [int(x) for x in input().split()]
n_rem = [n//5]*5
m_rem = [m//5]*5
for i in range(n%5):
    n_rem[(i+1)%5] += 1
for i in range(m%5):
    m_rem[(i+1)%5] += 1
print((n_rem[0]*m_rem[0] + n_rem[1]*m_rem[4] +
      n_rem[2]*m_rem[3] + n_rem[3]*m_rem[2] + n_rem[4]*m_rem[1]))



n, m = map(int, input().split())
a = [n // 5 + (n % 5 > i) for i in range(5)]
b = [m // 5 + (m % 5 > i) for i in range(5)]
ans = 0
for i in range(4): ans += a[i] * b[3 - i]
print(ans + a[4] * b[4])



n,m=list(map(int,input().split()))

nMod=[n//5]*5
mMod=[m//5]*5

for loop in range(1,n%5+1):
    nMod[loop]+=1

for loop in range(1,m%5+1):
    mMod[loop]+=1

print(nMod[0]*mMod[0]+nMod[1]*mMod[4]+nMod[4]*mMod[1]+nMod[2]*mMod[3]+nMod[3]*mMod[2])


n,m = list(map(int,input().split()))
n5 = [0]*5
for i in range(1,n+1):
    n5[i % 5] += 1
m5 = [0]*5
for i in range(1,m+1):
    m5[i % 5] += 1
print(n5[0] * m5[0]+n5[1] * m5[4] + n5[2] * m5[3] + n5[3] * m5[2] + n5[4] * m5[1])


from collections import defaultdict, deque, Counter, OrderedDict

def main():
    n,m = map(int, input().split())
    n1,n2 = divmod(n,5)
    m1,m2 = divmod(m,5)
    ans = n1*5*m1 + m2*n1 + m1*n2
    if n2 + m2 >= 5:
        ans += n2 + m2 - 4
    print(ans)




def __starting_point():
    """sys.setrecursionlimit(400000)
    threading.stack_size(40960000)
    thread = threading.Thread(target=main)
    thread.start()"""
    main()
__starting_point()

n, m = [int(x) for x in input().split()]
r = 0
for i in range(5):
    r += ((n+(5-i)%5)//5) * ((m+i)//5)
print(r)

n, m = list(map(int, input().split()))
r = 0
for i in range(1, n+1):
    x = (5 - i) % 5
    if x == 0:
        r += (m - x) // 5
    else:
        r += (m - x) // 5 + 1
print(r)


n,m=map(int,input().split())
k0=(n//5)*(m//5)
k1=(n//5+(n%5>0))*(m//5+(m%5>3))
k2=(n//5+(n%5>1))*(m//5+(m%5>2))
k3=(n//5+(n%5>2))*(m//5+(m%5>1))
k4=(n//5+(n%5>3))*(m//5+(m%5>0))
print(k0+k1+k2+k3+k4)

n, m = list(map(int, input().split()))
a = 5 * [n // 5]
for i in range(1, n % 5 + 1):
    a[i] += 1

b = 5 * [m // 5]
for i in range(1, m % 5 + 1):
    b[i] += 1

cnt = a[0] * b[0]
for i in range(1, 5):
    cnt += a[i] * b[5 - i]

print(cnt)


n, m = list(map(int, input().split()))
n_rem = [n // 5 for _ in range(5)]
for i in range(1, n % 5 + 1):
    n_rem[i] += 1
m_rem = [m // 5 for _ in range(5)]
for i in range(1, m % 5 + 1):
    m_rem[i] += 1
print(sum([n_rem[i] * m_rem[(5 - i) % 5] for i in range(5)]))


n,m = list(map(int,input().split()))
left_first = [n//5]*5
left_second = [m//5]*5
for i in range(n%5):
    left_first[i]+=1
    
for j in range(m%5):
    left_second[j]+=1

ans = left_first[-1]*left_second[-1]
for i in range(4):
    ans+=left_first[i]*left_second[3-i]
    #print(ans)
#print(left_first,left_second)
print(ans)


n, m = map(int, input().split())
A = [n//5, n//5, n//5, n//5, n//5]
B = [m//5, m//5, m//5, m//5, m//5]

for i in range(n%5):
    A[i]+= 1
for i in range(m%5):
    B[i]+= 1
print(A[0]*B[3] + A[3]*B[0] + A[1]*B[2] + A[2]*B[1] + A[4]*B[4])

x,y = map(int,input().split())
arx = []
ary = []
xx = x//5
arx = [xx,xx,xx,xx,xx]
for i in range(x%5):
    arx[i] += 1
yy = y//5
ary = [yy,yy,yy,yy,yy]
for i in range(y%5):
    ary[i] += 1
sum = 0
sum += arx[0]*ary[3]
sum += arx[1]*ary[2]
sum += arx[2]*ary[1]
sum += arx[3]*ary[0]
sum += arx[4]*ary[4]
print(sum)

import math

n,m = list(map(int, input().split()))

ndiv = math.floor(n/5)
nmod = n % 5

mdiv = math.floor(m/5)
mmod = m % 5

mods = 0
if nmod + mmod >= 5:
    mods = nmod + mmod - 4

ans = (ndiv * mdiv * 5) + nmod * mdiv + mmod * ndiv + mods
print(ans)


n, m = map(int, input().split())

full_n = n // 5
full_m = m // 5

print(full_n * full_m * 5 + full_n * (m%5) + full_m * (n%5) + sum(1 for x in range(0, n % 5 + 1) for y in range(0, m % 5 + 1) if (x + y) % 5 == 0) - 1)

n, m = list(map(int, input().split()))
cap = m // 5
others = m % 5

result = n * cap

cap2 = n // 5

result += cap2 * others

for i in range(cap2 * 5 + 1, cap2 * 5 + (n % 5) + 1):
    for j in range(cap * 5 + 1, cap * 5 + others + 1):
        if (i + j) % 5 == 0:
            result += 1

print(result)


d=lambda a,b: (a//5)*(b//5)
n,m=map(int,input().split())
print(d(n,m)+d(n+4,m+1)+d(n+3,m+2)+d(n+2,m+3)+d(n+1,m+4))

# coding: utf-8





import math
import string
import itertools
import fractions
import heapq
import collections
import re
import array
import bisect

def array2d(d1, d2, init = None):
    return [[init for _ in range(d1)] for _ in range(d2)]

n, m = list(map(int, input().split(" ")))

s = 0
for i in range(5):
    t1 = n//5
    t2 = m//5
    if i != 0:
        t1 += 1 if n % 5 >= i else 0
        t2 += 1 if m % 5 >= (5-i) else 0
    s += t1 * t2
print(s)


n, m = list(map(int, input().split()))
mod1, mod2, mod3, mod4, mod5 = n//5,n//5,n//5,n//5,n//5
if n%5 >= 1:
    mod1 += 1
if n%5 >= 2:
    mod2 += 1
if n%5 >= 3:
    mod3 += 1
if n%5 == 4:
    mod4 += 1

m1, m2, m3, m4, m5 = m//5, m//5, m//5, m//5, m//5
if m%5 >= 1:
    m1 += 1
if m%5 >= 2:
    m2 += 1
if m%5 >= 3:
    m3 += 1
if m%5 == 4:
    m4 += 1
#print(mod1, mod2, mod3, mod4, mod5, m1, m2, m3, m4, m5)
print(mod1*m4+mod2*m3+mod3*m2+mod4*m1+mod5*m5)


import sys


def main():
    x = sys.stdin.readline().split()
    n, m = int(x[0]), int(x[1])
    
    k = int(n/5)
    rest = n - k*5
    a = [k]*5
    for i in range(rest):
        a[i+1]+=1

    k = int(m/5)
    rest = m - k*5
    b = [k]*5
    for i in range(rest):
        b[i+1]+=1

    r = a[0]*b[0] + a[1]*b[4] + a[2]*b[3]+ a[3]*b[2] + a[4]*b[1]

    print(r)

main()


n, m = map(int, input().split())
n1 = [n // 5, (n - 1) // 5 + 1, (n - 2) // 5 + 1, (n - 3) // 5 + 1, (n - 4) // 5 + 1]
m1 = [m // 5, (m - 1) // 5 + 1, (m - 2) // 5 + 1, (m - 3) // 5 + 1, (m - 4) // 5 + 1]
#print(n1, m1)
print(n1[0] * m1[0] + n1[1] * m1[4] + n1[2] * m1[3] + n1[3] * m1[2] + n1[4] * m1[1])

n, m = list(map(int, input().split()))
nt = n // 5
mt = m // 5

nf = [nt] * 5
mf = [mt] * 5

for x in range((n % 5) + 1):
    nf[x] += 1

for x in range((m % 5) + 1):
    mf[x] += 1

nf[0] -= 1
mf[0] -= 1

ans = 0
for x in range(5):
    y = (5 - x) % 5
    ans += nf[x] * mf[y]

print(ans)


n, m = map(int, input().split())
zer1 = n // 5
zer2 = m // 5
one1 = (n - 1) // 5 + 1
one2 = (m - 1) // 5 + 1
two1 = (n - 2) // 5 + 1
two2 = (m - 2) // 5 + 1
three1 = (n - 3) // 5 + 1
three2 = (m - 3) // 5 + 1
four1 = (n - 4) // 5 + 1
four2 = (m - 4) // 5 + 1
print(zer1 * zer2 + one1 * four2 + two1 * three2 + three1 * two2 + four1 * one2)