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

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


int main()
{
    string a,b;
    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(a.size()<b.size() or a.size()==b.size() and A<B){
        auto c= sub(B,A);
        cout<<"-";
        for(int i =c.size()-1;i>=0;i--)cout<<c[i];
    }else{
    auto c= sub(A,B);
    for(int i =c.size()-1;i>=0;i--)cout<<c[i];
    }

    return 0;

}