#include<cstdio>
#include<cmath>
#include<iostream>
#include<algorithm>
#include<cctype>
#include<cstring>
using namespace std;
int main()
{
ios::sync_with_stdio(false);
	freopen("sub.in","r",stdin);
	freopen("sub.out","w",stdout);
	char a1[101],b1[101],t[101];
	int a[101],b[101],c[101],lengtha,lengthb,lengthc,i;
	memset(a,0,sizeof(a));
	memset(b,0,sizeof(b));
	memset(c,0,sizeof(c));
	cin>>a1>>b1;
	int la1=strlen(a1),lb1=strlen(b1);
	if(la1<lb1||la1==lb1&&strcmp(a1,b1)<0)
	{
		strcpy(t,a1);strcpy(a1,b1);strcpy(b1,t);
		cout<<'-';
	}
	lengtha=strlen(a1);lengthb=strlen(b1);
	for(i=0;i<lengtha;i++)a[lengtha-i]=a1[i]-48;
	for(i=0;i<lengthb;i++)b[lengthb-i]=b1[i]-48;
	i=1;
	//cout<<lengtha<<' '<<lengthb;
	while(i<=lengtha||i<=lengthb){
		if(a[i]<b[i]){
			a[i]+=10;
			a[i+1]--;
		}
		c[i]=a[i]-b[i];
		i++;
	}
	lengthc=i;
	/*for(i=lengthc;i>=1;i--)
		cout<<c[i];*/
	while(c[lengthc]==0&&lengthc>1)
		lengthc--;
	for(i=lengthc;i>=1;i--)
		cout<<c[i];
}