Problem:
Score : 100 points

Problem Statement

In K-city, there are n streets running east-west, and m streets running north-south. Each street running east-west and each street running north-south cross each other. We will call the smallest area that is surrounded by four streets a block. How many blocks there are in K-city?

Constraints

2 ≤ n, m ≤ 100

Input

Input is given from Standard Input in the following format:

n m

Output

Print the number of blocks in K-city.

Sample Input 1

3 4

Sample Output 1

6

There are six blocks, as shown below:

Sample Input 2

2 2

Sample Output 2

1

There are one block, as shown below:

Solution in Pascal (FPC 2.6.2) (judge verdict: Accepted)

program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils,Classes;
var
  a,h,w,i,j,count,x,y,sw,m,n,b,c,soeji,sum,max,k,min:Integer;
  //l:array[0..6] of Integer = (1,2,4,8,16,32,64);
  s,s123,s1,s2,s3:string;
  tf:Boolean;
  nyu:TStringList;
begin
  try
    { TODO -oUser -cConsole Main : ここにコードを記述してください }
    Read(n);
    Readln(m);

    Writeln((n-1)*(m-1));
    Readln;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.