var f:array[..,..] of int64;

     n,m,j,i:longint;

 begin

   readln(m,n);

   for i:= to n do

     f[i,]:=;

   for i:= to m do

     f[,i]:=*i;

   for i:= to n do

     for j:= to m do

       f[i,j]:=f[i,j-]+f[i-,j-];

   writeln(f[n,m]);

 end.