#include <bits/stdc++.h>
using namespace std;
class bignum
{
private:
	/*
		传入两个高精度正数wa和wb。
		如果wa小于wb返回true否则返回false。
	*/
	bool cmp(const string &wa, const string &wb)
	{
		if (wa.size() < wb.size())
			return 1;
		if (wa.size() > wb.size())
			return 0;
		int len = wa.size();
		for (int i = 0; i < len; i++)
		{
			if (wa[i] == wb[i])
				continue;
			return wa[i] < wb[i];
		}
		return 0;
	}
	/*
		传进来两个高精度整数返回wa - wb的值。
		要求wa >= wb，例如:wa = 123, wb = 24。sub(wa, wb) = 99.
	*/
	string sub(const string &wa, const string &wb)
	{
		string a = wa, b = wb;
		reverse(a.begin(), a.end()), reverse(b.begin(), b.end());

		string res = "";
		for (int i = 0, t = 0; i < (int)a.size(); i++)
		{
			t = (a[i] - '0') - t;
			if (i < (int)b.size())
				t -= (b[i] - '0');
			res.push_back((t + 10) % 10 + '0');
			t < 0 ? t = 1 : t = 0;
		}

		while ((int)res.size() > 1 && res.back() == '0')
			res.pop_back();
		reverse(res.begin(), res.end());
		return res;
	}

	/*
		传进来一个高精度整数wa和一个int类型的整数b。
		返回wa / b的值。
		例如：wa = 124, b = 4, div(wa, b) = 31.
	*/
	string div(const string &wa, int b)
	{
		string a = wa, res = "";
		reverse(a.begin(), a.end());
		int r = 0;
		for (int i = (int)a.size() - 1; i >= 0; i--)
		{
			r = r * 10 + (a[i] - '0');
			res.push_back((r / b) + '0');
			r %= b;
		}
		reverse(res.begin(), res.end());
		while ((int)res.size() > 1 && res.back() == '0')
			res.pop_back();
		reverse(res.begin(), res.end());
		return res;
	}

	/*
		传进来一个高精度整数wa和一个int类型的整数b。
		返回wa * b的值。
		例如：wa = 124, b = 4, mul(wa, b) = 496.
	*/
	string mul(const string &wa, int b)
	{
		string a = wa, res = "";
		reverse(a.begin(), a.end());

		int t = 0;
		for (int i = 0; i < (int)a.size() || t; i++)
		{
			if (i < (int)a.size())
				t += (a[i] - '0') * b;
			res.push_back((t % 10) + '0');
			t /= 10;
		}

		while ((int)res.size() > 1 && res.back() == 0)
			res.pop_back();

		reverse(res.begin(), res.end());
		return res;
	}

public:
	string num;
	bignum(string b = "0")
	{
		num = b;
	}

	/*
		传进来一个高精度整数，如果是偶数返回true，奇数返回false.
	*/
	bool check(const string &a)
	{
		return !((a.back() - '0') & 1);
	}
	bignum operator*(int b)
	{
		return bignum(mul(this->num, b));
	}
	bignum operator/(int b)
	{
		return bignum(div(this->num, b));
	}
	bignum operator-(string b)
	{
		return bignum(sub(this->num, b));
	}
	bool operator<(string b)
	{
		return cmp(this->num, b);
	}
	bool operator>(string b)
	{
		return cmp(b, this->num);
	}
	void operator=(string a)
	{
		this->num = a;
	}
};