#include <bits/stdc++.h>
using namespace std;

string A,B;
//比较是否有a>=b 
bool cmp(vector<int> &a,vector<int> &b)
{
	if(a.size()!=b.size())return a.size()>b.size();
	
	for(int i=a.size()-1;i>=0;i--)
		if(a[i]!=b[i])
			return a[i]>b[i];
	
	return true; 
}

vector<int> sub(vector<int> &a,vector<int> &b)
{
	vector<int> c;
	
	for(int i=0;i<a.size();i++)
	{
		if(a[i]<b[i])
		{
			a[i] += 10;
			a[i+1]--;
		}
		c.push_back(a[i]-b[i]);
	}
	while(c.size()>1&&c.back()==0)c.pop_back();
	
	return c;
}

int main()
{
	cin>>A>>B;
	vector<int> a,b;
	
	for(int i=A.size()-1;i>=0;i--)
		a.push_back(A[i]-'0');
	for(int i=B.size()-1;i>=0;i--)
		b.push_back(B[i]-'0');
	
	if(cmp(a,b))
	{
		auto c = sub(a,b);
		
		for(int i=c.size()-1;i>=0;i--)
			printf("%d",c[i]);
	}
	else
	{
		auto c = sub(b,a);
		
		printf("-");
		for(int i=c.size()-1;i>=0;i--)
			printf("%d",c[i]);
	}
	
	return 0;
}