{
TASK:crossing
LANG:Pascal
}
program crossing;
var Shir,Premes:real;
    Vld,Vvd:real;
    t:real;             a:string;   code:integer;
    ch,min,sek:real;       j:integer;
begin
 read(Shir,premes,vld);
 readln(Vvd);
 t:=( shir/vld)+((premes-shir)/vvd);
 t:=t*3600;
ch:=int(t);
min:= round(t/60);
sek:= round(t/3600);
 writeln(ch);


end.
