var
  d,i,j,k,a,b:longint;
  f:array[0..1000,0..1000]of longint;

function min(x,y:longint):longint;
begin
  if x<y then exit(x);
  exit(y);
end;

function go(x,y:longint):longint;
var
  i,t:longint;
begin
  if (x<=1000)and(y<=1000)and(f[x,y]<>-9) then exit(f[x,y]);
  t:=x*y;
  for i:=2 to min(x,y) do dec(t,go((x div i),(y div i)));
  f[x,y]:=t;
  exit(t);
end;

begin
  assign(input,'parents.in');reset(input);
  assign(output,'parents.out');rewrite(output);
  for i:=0 to 1000 do
   for j:=0 to 1000 do
   f[i,j]:=-9;
  f[0,0]:=0;
  readln(a,b,d);
  if (a=d)or(b=0) then writeln(0)
  else writeln(go((a div d),(b div d)));
  close(input);
  close(output);
end.