#include<bits/stdc++.h>
using namespace std;
vector<int> res,x,y;
bool vector_swap(vector<int> x,vector<int> y)
{
    if(x.size()>y.size())return true;
    if(x.size()<y.size())return false;
    for(int i=0;i<x.size();i++)
    {
    if(x[i]>y[i])return true;
    if(x[i]<y[i])return false;
}
    return true;
}
vector<int> minuse(vector<int> x,vector<int> y)
{
    int t=0;
    reverse(x.begin(),x.end());
    reverse(y.begin(),y.end());
    for(int j=0;j<x.size();j++)
    {
    int s=0;
    if(j<y.size())s-=y[j];
    s+=(x[j]+t);
    if(s>=0)res.push_back(s),t=0;
    else res.push_back(s+10),t=-1;
    }
    int i=res.size()-1;
    while(i>0&&res[i]==0)i--,res.pop_back();
    return res;
}
int main()
{
    string a,b;
    cin>>a>>b;
    for(int i=0;i<a.size();i++)x.push_back(a[i]-'0');
    for(int i=0;i<b.size();i++)y.push_back(b[i]-'0');
    if(vector_swap(x,y)==false)swap(x,y),cout<<'-';
    minuse(x,y);
    for(int i=res.size()-1;i>=0;i--)
    cout<<res[i];
    return 0;
}