#include<bits/stdc++.h>
using namespace std;
int a[10001],b[10001],c[10001];
int main()
{
	string s1,s2;
	cin>>s1>>s2;
	int l1=s1.size();
	int	l2=s2.size();
	if(l1<l2||(l1==l2&&s1<s2))
	{
		string t=s1;
		s1==s2;
		s2==t;
	}
	l1=s1.size();
	l2=s2.size();
	///////
	for(int i=0;i<l1;i++)
	{
		a[i]=s1[l1-1-i]-'0';
	}
	for(int i=0;i<l2;i++)
	{
		b[i]=s2[l2-1-i]-'0';
	}
	///////////
	for(int i=0;i<l1;i++)
	{	
		if(l1>l2)
		{
			if(a[i]<b[i])
			{
			--a[i+1];
			a[i]+=10;
			}
			c[i]=a[i]-b[i];
			continue;
		}
		if(l1<l2)
		{
			if(a[i]<b[i])
			{
				--a[i+1];
				a[i]+=10;
			}
			c[i]=b[i]-a[i];
			continue;
		}
	}
	////////////
	int k=l1-1;
	while(c[k]==0)
	k--;
	for(int i=k;i>=0;i--)
	{
		if(l1>l2);
		cout<<c[i];
		if(l1<l2)
		cout<<"-"<<c[i];
	}
	return 0;
}