#include<bits/stdc++.h>
using namespace std;
vector<int> count(vector<int> a,vector<int> b)
{
	vector<int> c;
	if(a.size()!=b.size())
	{
		while(a.size()!=b.size()) b.push_back(0);
	}
	for(int i=0;i<a.size();++i)
	{
		if(a[i]==-1||a[i]<b[i])
		{
			a[i+1]-=1;
			a[i]+=10;
		}
		c.push_back(a[i]-b[i]);
	}
	for(int i=c.size()-1;c.size()!=1;--i)
	{
		if(c[i]==0) c.pop_back();
		else break;
	}
	return c;
}
int main()
{
	string A,B;
	cin>>A>>B;
	vector<int> a,b;
	if(A<B)
	{
		swap(A,B);
		cout<<"-";
	}
	for(int i=A.size()-1;i>=0;--i) a.push_back(A[i]-48);
	for(int i=B.size()-1;i>=0;--i) b.push_back(B[i]-48);
	vector<int> c=count(a,b);
	for(int i=c.size()-1;i>=0;--i) cout<<c[i];
	return 0;
}