bool operator>=(const Bigint &lhs, const Bigint &rhs) { if(lhs.compare(rhs)>=0) return true; return false; }
int Bigint::compare(const Bigint& number1, const Bigint& number2) { return number1.compare(number2); }
bool operator<(const Bigint &lhs, const Bigint &rhs) { if(lhs.compare(rhs)==-1) return true; return false; }