private int heightOfPhi(int Phi){
  if (Phi == 0) {
    return -1;
  }
  int Tau=0;
  int modul=1;
  while (Phi % modul == 0) {
    modul*=2;
    Tau+=1;
  }
  return Tau - 1;
}

private int heightOfPhi ( int Phi ) { if ( Phi == 0 ) { return - 1 ; } int Tau = 0 ; int modul = 1 ; while ( Phi % modul == 0 ) { modul *= 2 ; Tau += 1 ; } return Tau - 1 ; }
returns the largest h such that 2 ^ h | phi
