#include<iostream>
#include<string.h>
using namespace std;
const int INF=0x3f3f3f3f;
const int N=2e5+10;
string a,b;
int lena,lenb,lenc,a1[N],b1[N],c1[N],x; 
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=max(lena,lenb);
	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];
	}
}