#include <fstream>
#include <string>
using namespace std;
ifstream fin("sub.in");
ofstream fout("sub.out");
string sub(string a,string b)
{
	int lx,ly,m[101],n[101],z[101],i,k,lmax;bool fu;
	string c;
	lx=a.length();ly=b.length();
	if(lx>ly)
		lmax=lx;
	else
		lmax=ly;
	if(lx<ly||(lx==ly&&a<b))
	{
		fu=true;c=a;a=b;b=c;k=lx;lx=ly;ly=k;
	}
	else
		fu=false;
	for(i=1;i<=lmax;i++)
		m[i]=n[i]=z[i]=0;
	for(i=lx-1;i>=0;i--)
		m[lx-i]=a[i]-'0';
	for(i=ly-1;i>=0;i--)
		n[ly-i]=b[i]-'0';
	for(i=1;i<=lmax;i++)
	{
		z[i]+=m[i]-n[i];
		if(z[i]<0)
		{
			z[i]+=10;
			z[i+1]-=1;
		}
	}
	while(z[lmax]==0&&lmax>0)
		if(z[lmax]==0)
			lmax--;
	c="";
	if(a==b)
		fout<<0<<endl;
	else
	{
	for(i=lmax;i>=1;i--)
		c+=char(z[i]+'0');
	}
	if(fu)
		c="-"+c;
	return c;
}
int main()
{
	string x,y;
	fin>>x>>y;
	fout<<sub(x,y)<<endl;
	fin.close();
	fout.close();
	return 0;
}