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 <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/172ce45a535a02e9d636dcf4c462a2a1df6c3215.png" style="max-width: 100.0%;max-height: 100.0%;"/> equals 0.

As usual, Alyona has some troubles and asks you to help.
The only line of the input contains two integers *n* and *m* (1 ≤ *n*, *m* ≤ 1 000 000).
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.
6 12
14
11 14
31
1 5
1
3 8
5
5 7
7
21 21
88
10 15
30
1 1
0
1 1000000
200000
1000000 1
200000
1000000 1000000
200000000000
944 844
159348
368 984
72423
792 828
131155
920 969
178296
640 325
41600
768 170
26112
896 310
55552
320 154
9856
744 999
148652
630 843
106218
54 688
7431
478 828
79157
902 184
33194
31 29
180
751 169
25384
879 14
2462
7 858
1201
431 702
60512
855 355
60705
553 29
3208
721767 525996
75929310986
805191 74841
12052259926
888615 590981
105030916263
4743 139826
132638943
88167 721374
12720276292
171591 13322
457187060
287719 562167
32349225415
371143 78307
5812618980
487271 627151
61118498984
261436 930642
48660664382
377564 446782
33737759810
460988 28330
2611958008
544412 352983
38433636199
660540 869123
114818101284
743964 417967
62190480238
827388 966812
159985729411
910812 515656
93933134534
26940 64501
347531388
110364 356449
7867827488
636358 355531
45248999219
752486 871672
131184195318
803206 420516
67552194859
919334 969361
178233305115
35462 261309
1853307952
118887 842857
20040948031
202311 358998
14525848875
285735 907842
51880446774
401863 456686
36705041203
452583 972827
88056992428
235473 715013
33673251230
318897 263858
16828704925
402321 812702
65393416268
518449 361546
37488632431
634577 910391
115542637921
685297 235043
32214852554
801425 751183
120403367155
884849 300028
53095895155
977 848872
165869588
51697 397716
4112144810
834588 107199
17893399803
918012 688747
126455602192
1436 237592
68236422
117564 753732
17722349770
200988 302576
12162829017
284412 818717
46570587880
400540 176073
14104855884
483964 724917
70166746198
567388 241058
27354683301
650812 789902
102815540084
400999 756281
60653584944
100 101
2020
100 102
2040
103 100
2060
100 104
2080
3 4
3
11 23
50
8 14
23
23423 34234
160372597
1 4
1
999999 999999
199999600001
82 99
1624
21 18
75
234 234
10952
4 4
4
6 13
15
3 9
6
99999 99999
1999960001
34 33
225
2 2
0
333 1
66
3 3
2
8 2
3
2179 2218
966605
1000000 999999
199999800000
873828 774207
135304750879
13 19
50
1648 576469
190004183
11 13
28
5 8
8
650074 943659
122689636154
1 3
0
54 43
465
14 9
26
2 3
1
543 534
57993
321 123
7896
21 3
12
2 1
0
4 3
3
47474 74747
709707816
4 9
8
7 4
6
9 4
8
12414 4214
10462520
2 9
4
253 821
41542
2 4
2
n, m = 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
res=0

res+=a[0]*b[0]
for j in range(1,5):
    res+=a[j]*b[5-j]
print(res)
