p03280 AtCoder Beginner Contest 106 - Garden_9775
There is a farm whose length and width are A yard and B yard, respectively. A farmer, John, made a vertical road and a horizontal road inside the farm from one border to another, as shown below: (The gray part represents the roads.)



What is the area of this yard excluding the roads? Find it.

Constraints

* A is an integer between 2 and 100 (inclusive).
* B is an integer between 2 and 100 (inclusive).

Input

Input is given from Standard Input in the following format:


A B


Output

Print the area of this yard excluding the roads (in square yards).

Examples

Input

2 2


Output

1


Input

5 7


Output

24
#abc106a

a,b=map(int,raw_input().split())
print a*b-a-b+1

5 7 2 2 6 7 2 1 6 12 0 2 0 4 9 2 2 4 -1 2 -1 4 -1 5 0 0 7 2 0 -1 -1 -1 -2 -2 0 -11 -11 2 -11 3 -11 4 2 -4 -22 4 2 -6 -21 4 0 -6 -21 8 -33 8 -1 -7 -33 13 -36 13 -1 -6 -36 17 -1 17 -1 -8 0 17 -1 -9 -2 -7 2 14 5 0 2 20 2 42 0 42 0 79 0 40 -4 -1 0 52 0 36 -4 -2 -4 0 0 66 -4 3 -5 4 -8 2 0 14 -6 -2 4 14 -8 -2 -8 -3 -12 -1 6 10 8 -1 -18 2 0 -10 -1 -19 -2 10 -1 -15 -1 -24 -1 -21 -3 6 -2 -21 -1 16 -4 -13 -1 15 -1 12 -1 23 -2 40 -2 72 -2 78 -2 30 -2 56 -4 4 -4 6 -7 6 3 12 18 -1 18 -3 -13 4 0 -33 0 -53 0 -105 -10 -2 -1 -105 -2 -105 -6 -3 -2 -162 -3 -162 -4 -162 -4 -84 -4 -27 -1 -27 -1 -38
24 1 30
 0
 55
 -1
 -3
 8
 3
 -2
 -6
 -8
 1
 6
 2
 4
 9
 12
 -12
 -24
 -36
 -5
 -69
 -7
 -66
 7
 -154
 -238
 16
 -408
 -444
 14
 -592
 -32
 18
 -16
 20
 24
 13
 -4
 19
 41
 -41
 -78
 -39
 10
 -51
 -35
 15
 5
 -65
 -10
 -18
 -9
 -13
 21
 39
 27
 36
 26
 45
 -14
 -19
 11
 40
 -27
 32
 50
 44
 -20
 66
 -30
 70
 -28
 -22
 -44
 -117
 -213
 -231
 -87
 -165
 -15
 -25
 -40
 22
 -34
 -68
 -42
 34
 54
 106
 33
 212
 318
 28
 489
 652
 815
 425
 140
 56
 78
