#include <iostream>
#include <vector>
using namespace std;

bool cmp(string &s1,string &s2)
{
    if (s1.size() != s2.size())
        return s1.size() > s2.size();
    for (int i = 0;i < s1.size();++i)
        if (s1[i] != s2[i]) return s1[i] > s2[i];
    return true;
}

vector<int> sub(vector<int>& v1,vector<int>& v2)
{
    vector<int> v3;
    for (int i = 0,t = 0;i < v1.size();++i)
    {
        t = v1[i] - t;
        if (i < v2.size())  t -= v2[i];
        v3.push_back((i + 10) % 10);
        t = t < 0 ? 1 : 0;
    }
    while (v3.size() > 1 && v3.back() == 0) v3.pop_back();
    return v3;
}

int main(void)
{
    string s1,s2;
    cin>>s1>>s2;
    vector<int> v1,v2,v3;
    for (int i = (int)s1.size() - 1;i > -1;--i)
        v1.push_back(s1[i] - '0');
    for (int i = (int)s2.size() - 1;i > -1;--i)
        v2.push_back(s2[i] - '0');
    if (cmp(s1,s2)) v3 = sub(v1,v2);
    else    v3 = sub(v2,v1),printf("-");
    for (int i = (int)v3.size() - 1;i > -1;--i)
            printf("%d",v3[i]);
    return 0;
}