calc

program calc;
var
    N:integer;
    M:integer;
    X:integer;
    Y:integer;
    result_a:real;
    result_b:real;
begin
    readln(N);
    readln(M);
    readln(X);
    readln(Y);

    if N/X > int(N/X) then result_a := int(N/X) + 1 else result_a := int(N/X);
    if M/Y > int(M/Y) then result_b := int(M/Y) + 1 else result_b := int(M/Y);

    writeln(result_a + result_b:0:0);
end.