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

int main()
{
#ifndef ONLINE_JUDGE
   freopen ("input.txt", "r", stdin);
   freopen ("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    string s,s1;
    int i,a[101] = {},b[101] = {},flag = 0,temp = 0;
    cin >> s >> s1;
    if (s.size() < s1.size())
    {
        s.swap(s1);
    }
    for (i = 0 ; i < s.size() ; i++)
    {
        a[i] = s[i] - 48;
    }
    for (i = (s.size() - s1.size()) ; i < s.size() ; i++)
    {
        b[i] = (s1[i-(s.size() - s1.size())] - 48);
    }
    for (i = s.size() - 1 ; i > -1;i--)
    {
        if (a[i] - b[i] - flag < 0)
        {
            a[i] = a[i] + 10 - b[i] - flag;
            flag = 1;
        }
        else
        {
            a[i] = a[i] - b[i] - flag;
        }
    }
    for (i = 0 ; i < s.size() ; i++)
    {
        temp = temp * 10 + a[i];
    }
    cout << temp;
    return 0;
}