#include<bits/stdc++.h>
using namespace std;
string s1,s2;
int a[510],b[510],ans[510],i,c,t;
int main(){
	cin>>s1>>s2;	
	for(i=0;i<s1.size();i++){
		a[i]=s1[s1.size()-1-i]-'0';
	}
	for(i=0;i<s2.size();i++){
		b[i]=s2[s2.size()-1-i]-'0';
	}
	for(i=0;i<max(s1.size(),s2.size());i++){
		ans[i]=(a[i]-b[i])-c;
		if(ans[i]<0){ans[i]+=10; c=1;}
	}
	if(c==0){
		t=max(s1.size(),s2.size())-1;
		while(ans[t]==0) t--;
		for(i=t;i>=0;i--) cout<<ans[i];
		return 0;
	}
	c=0;
	for(i=0;i<max(s1.size(),s2.size());i++){
		ans[i]=(b[i]-a[i])-c;
		if(ans[i]<0){ans[i]+=10; c=1;}
	}
	cout<<"-";
	t=max(s1.size(),s2.size())-1;
	while(ans[t]==0) t--;
	for(i=t;i>=0;i--) cout<<ans[i];
	return 0;
}