program romeo;
var x,y,i,j,k,m,z,e1,e2:longint;consum,s1,s2:int64;
    f,g:text;
begin
assign(f,'romeo.in');reset(f);
assign(g,'romeo.out');rewrite(g);
read(f,x,y);s1:=0;s2:=0;
if x>=y-1 then consum:=x+y
          else begin
               z:=y div(x+1);
               k:=y mod(x+1);
               for i:=1 to z do inc(s1,i);
               m:=x+1-k;
               e1:=m*s1;
               for i:=1 to z+1 do inc(s2,i);
               e2:=k*s2;
               consum:=e1+e2+x;
               end;
writeln(g,consum);
close(f);close(g);
end.