public PS CHIA(PS t2)
{
PS t = new PS();
t.ts = this.ts * t2.ms;
t.ms = this.ms * t2.ts;
return(t.Rutgon());
}
public PS Tong(PS t2)
{
PS t = new PS();
t.ts = this.ts * t2.ms + t2.ts * this.ms;
t.ms = this.ms * t2.ms;
return(t.Rutgon());
}