#include<bits/stdc++.h> 
using namespace std;
int a[205],b[205],ans[205];
int main()
{
    string s1,s2;
	cin>>s1>>s2; 
	if(s2.size()>s1.size()||s2.size()==s1.size()&&s2>s1)
	{
		swap(s1,s2);
		cout<<"-";
	}
	reverse(s1.begin(),s1.end());
	reverse(s2.begin(),s2.end());
	for(int i=0;i<s1.size();i++)
	{
		a[i]=s1[i]-'0';
	}
	for(int i=0;i<s2.size();i++)
	{
		b[i]=s2[i]-'0';
	}
	int len=max(s1.size(),s2.size()); 
	for(int i=0;i<=len;i++)
	{
		if(a[i]<b[i]) 
		{
			a[i+1]--;
			a[i]=a[i]+10;
		}
		ans[i]=a[i]-b[i];
	}
	len++;
	while(ans[len]==0 && len>0)
	{
        len--;
	}
	for(int i=len;i>=0;i--)
	{
	    cout<<ans[i];
	}
	return 0;
}