#define M 10000

struct BigInt {
	int a[100], len, sign;
	void compact()
	{
		while (len > 1 && !a[len-1]) --len;
		if (!len) len = 1;
		if (1 == len && !a[0]) sign = 0;
	}
	void operator = (int n)
	{
		if (n < 0) sign = 1, n = -n; else sign = 0;
		for (len = 0; n; ++len) a[len] = n % M, n /= M;
		if (!len) a[0] = 0, len = 1;
	}
	void operator = (const BigInt &bi)
	{
		len = bi.len;
		sign = bi.sign;
		memcpy(a, bi.a, len * sizeof(a[0]));
	}
	BigInt operator * (const BigInt &bi) const
	{
		int i, j, k;
		BigInt rs;
		rs.sign = (sign ^ bi.sign);
		rs.len = len + bi.len;
		memset(rs.a, 0, rs.len*sizeof(a[0]));
		for (i = 0; i < len; ++i)
			for (j = k = 0; j < bi.len || k; ++j)
			{
				k += rs.a[i+j];
				if (j < bi.len) k += a[i]*bi.a[j];
				rs.a[i+j] = k % M;
				k /= M;
			}
		rs.compact();
		return rs;
	}
	bool AbsLess(const BigInt &bi) const
	{
		if (len != bi.len) return len < bi.len;
		for (int i = len; --i >= 0; )
			if (a[i] != bi.a[i]) return a[i] < bi.a[i];
		return false;
	}
	void operator += (const BigInt &bi)
	{
		int i, j;
		if (sign == bi.sign) {
			for (i = j = 0; i < len || i < bi.len || j; ++i)
			{
				if (i < len) j += a[i];
				if (i < bi.len) j += bi.a[i];
				a[i] = j % M;
				j /= M;
			}
			if (i > len) len = i;
		} else {
			if (AbsLess(bi)) {
				BigInt t = *this;
				*this = bi;
				for (i = j = 0; i < t.len || j; ++i)
				{
					if (i < t.len) j += t.a[i];
					a[i] -= j;
					if (a[i] < 0) j = 1, a[i] += M; else j = 0;
				}
			} else {
				for (i = j = 0; i < bi.len || j; ++i)
				{
					if (i < bi.len) j += bi.a[i];
					a[i] -= j;
					if (a[i] < 0) j = 1, a[i] += M; else j = 0;
				}
			}
		}
		compact();
	}
	void output()
	{
		int i = len;
		compact();
		if (sign) putchar('-');
		printf("%d", a[--i]);
		while (--i >= 0) printf("%04d", a[i]);
	}
}