#include <iostream>
#include <vector>

using namespace std;

bool cmp(vector<int> &A, vector<int> &B)
{
    if(A.size() != B.size()) return A.size() > B.size();
    else
    {
        for(int i = A.size() - 1; 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;
    int t = 0;
    for(int i = 0; i < A.size(); i ++ )
    {
        if(i < B.size()) t = A[i] - B[i] - t;
        else t = A[i] - t;
        C.push_back((t + 10) % 10);
        if(t >= 0) t = 0;
        else t = 1;
    }
    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))
    {
        auto C = sub(A, B);
        for(int i = C.size() - 1; i >= 0; i -- ) printf("%d", C[i]);
    }
    else
    {
        printf("-");
        auto C = sub(B, A);
        for(int i = C.size() - 1; i >= 0; i -- ) printf("%d", C[i]);
    }
}