#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<string>
#include<cstring>
const int INF=0x3f3f3f3f;
const int N=1e5+10;
using namespace std;
string a,b;
int a1[N],b1[N],c1[N],lena,lenb,lenc;
int main(){
	cin>>a>>b;
	lena=a.size();
	lenb=b.size();
	if(lena<lenb||(lena == lenb&&a<b))
	{
		swap(lena,lenb);
		swap(a,b);
		cout<<"-";
	}
	for(int i=0;i<lena;i++)
	{
		a1[i]=a[lena-i-1]-'0';
	}
	for(int i=0;i<lenb;i++)
		b1[i]=b[lenb-i-1]-'0';
		lenc =lena;
		for(int i =0;i<lenc;i++)
		{
			c1[i]=a1[i]-b1[i];
			if(c1[i]<0)
			{
				a1[i+1]--;
				c1[i] += 10;
			}
		}
		while(c1[lenc]==0&&lenc>0)
		lenc--;
		
		for(int i=lenc;i>=0;i--)
		cout<<c1[i];
	return 0;
}