#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
typedef long long LL;
const int n = 1e6 + 10;
bool cmp(vector<int>& A, vector<int>& B)
{
if (A.size() != B.size())return A.size() > B.size();
for (int i = A.size(); i >= 0; i--)
{
if (A[i] != B[i])
return A[i] > B[i];
}
return true;
}
vector<int> sub(vector<int>& A, vector<int>& B)
{
vector<int> C;
for (int i = 0, t = 0; i < A.size(); i++)
{
t = A[i] - t;
if (i < B.size())t -= B[i];
C.push_back((t + 10) % 10);
if (t < 0)t = 1;
else t = 0;
}
while (C.size() > 1 && C.back() == 0)C.pop_back();
return C;
}
int main()
{
string a, b;
vector<int>A, B;
cin >> 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 (cmp(A, B))
{
vector<int> c = sub(A, B);
for (int i = c.size() - 1; i >= 0; i--)cout << c[i];
}
else
{
vector<int> c = sub(B, A);
cout << '-';
for (int i = c.size() - 1; i >= 0; i--)cout << c[i];
}
return 0;
}