#include <bits/stdc++.h>
using namespace std;
#define LL long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
int x[N] ,y[N];
int main()
{
	string a,b;
	int flag = 0;
	cin >> a >> b;
	int lena = a.size();
	int lenb = b.size();
	if(lenb > lena )
		flag = 1;
	if(lena == lenb && b > a)
		flag = 1;
	if(flag)
	{
		swap(a,b);
		swap(lena, lenb);
		cout << "-";
	}
	for(int i = 0 ; i < lena ; i++)
		x[i] = a[lena - i - 1] - '0';
	for(int i = 0 ; i < lenb ; i++)
		y[i] = b[lenb - i - 1] - '0';

	for(int i = 0 ; i < lena ; i++)
	{
		x[i] -= y[i];
		if(x[i] < 0)
		{	
			x[i] += 10;
			x[i+1]--;
		}
	}
	while(x[lena] == 0 && lena > 0)
		lena--;
	for(int i = lena ; i >= 0 ; i--)
		cout << x[i];
	return 0;
}