#include<bits/stdc++.h>
using namespace std;
#define el "\n"
#define ll long long
#define ull unsigned long long
#define se second
#define fi first
#define be begin()
#define en end()
#define Faster cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(0);

int main()
{
    Faster;
    string a, b; cin >> a >> b;
    int ok = 0;
    string s = "";
    if(a.size() < b.size())
    {
        swap(a,b);
        ok = 1;
    }
    if(a.size() == b.size() && a < b)
    {
        swap(a,b);
        ok = 1;
    }
    string tmp = "";
    for(int i = 0; i < a.size() - b.size(); i++)
    {
        tmp += '0';
    }
    b= tmp + b;
    int du = 0;
    for(int i = a.size() - 1; i >= 0; i--)
    {
        int x = a[i] - '0';
        int y = b[i] - '0' + du;
        if(x < y)
        {
            x += 10;
            du = 1;
        }
        else
        {
            du = 0;
        }
        s += to_string(x  - y);
    }
    if(s.size() > 1 && s.back() == '0') s.pop_back();
    if(ok == 1) cout << "-";
    reverse(s.begin(), s.end());
    cout << s;
    return 0;
}