#include<iostream>
using namespace std;

const int N = 1e5 + 10;
string a , b;
int a1[N] , b1[N] , c1[N] , lena , lenb , lenc , x;

int main(){
	cin >> a >> b;
	lena = a.size();
	lenb = b.size();
	if(lena < lenb || (lena == lenb && a < b)){
		swap(a,b);
		swap(lena,lenb);
		cout << '-' ;
	}
	lenc = max(lena , lenb);
	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';
	}for(int i = 0;i < lenc;i ++){
		c1[i] = a1[i] - b1[i];
		if(c1[i] < 0){
			c1[i] += 10;
			a1[i + 1] --;
		}
	}
	c1[lenc] = x;
	while(c1[lenc] == 0 && lenc > 0){
		lenc --;
	}for(int i = lenc;i >= 0;i --){
		cout << c1[i];
	}
	return 0;
}