public static BigInteger calculateA(BigInteger p,BigInteger q,BigInteger gA,BigInteger x2s){
  return gA.modPow(x2s,p);
}

public static BigInteger calculateA ( BigInteger p , BigInteger q , BigInteger gA , BigInteger x2s ) { return gA . modPow ( x2s , p ) ; }
calculate a as done in round 2 .
