#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int MAXX = 100001;
int a[MAXX], b[MAXX], c[MAXX];
char n[MAXX], n1[MAXX], n2[MAXX];
int main()
{
	int lena, lenb, lenc, i;
	gets(n1);
	gets(n2);
	if(strlen(n1) < strlen(n2) || (strlen(n1) == strlen(n2) && strcmp(n1, n2) < 0))
	{
		strcpy(n, n1);
		strcpy(n1, n2);
		strcpy(n2, n);
		cout << "-";
	}
	lena = strlen(n1); lenb = strlen(n2);
	for(i = 0; i <= lena - 1; i ++) a[lena - i] = int(n1[i] - '0');
	for(i = 0; i <= lenb - 1; i ++) b[lenb - i] = int(n2[i] - '0');
	i = 1;
	while(i <= lena || i <= lenb)
	{
		if(a[i] < b[i])
		{
			a[i] += 10;
			a[i + 1] --;
		}
		c[i] = a[i] - b[i];
		i ++;
	}
	lenc = i;
	while((c[lenc] == 0) && (lenc > 1)) lenc --;
	for(i = lenc; i >= 1; i --) cout << c[i];
	cout << endl;
	return 0;	
}