#include <iostream>
#include <vector>

using namespace std;

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() - 1; i >= 0; i--) {
        if(A[i] != B[i]) return A[i] > B[i];
    }
    return A[0] >= B[0];
}

vector<int> sub(vector<int> &A, vector<int> &B) {
    vector<int> C;
    int t = 0;
    for (int i = 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, res;
    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)) {
        res = sub(A, B);
    }else {
        res = sub(B, A);
        cout << '-';
    }

    for (int i = res.size() - 1; i >= 0; i--) cout << res[i];
    cout << endl; 
    return 0;
}