#include<iostream>
#include<cstring>
#include<vector>
#include<algorithm>

using namespace std;

int main(){
    string buff = "";
    string a, b;
    cin >> a >> b;
    reverse(a.begin(), a.end());
    reverse(b.begin(), b.end());
    int l1 = a.size(), l2 = b.size();
    int n = max(l1, l2);
    vector<int> ans(n);
    for(int i = 0; i < n; i++){
        ans[i] += (i < l1 ? a[i] - '0' : 0) - (i < l2 ? b[i] - '0' : 0);
    }
    for(int i = 0; i < n - 1; i++){
        if(ans[i] < 0){
            int temp = (-ans[i] - 1) / 10 + 1;
            ans[i] += temp * 10;
            ans[i + 1] -= temp;
        }
    }
    for(int i = n - 1; i >= 0; i--){
        if(ans[i] == 0){
            continue;
        }
        if(ans[i] > 0){
            break;
        }
        if(ans[i] < 0){
            ans[i] += 1;
            buff += '-';
            ans[i] = abs(ans[i]);
            while(i){
                i--;
                ans[i] = 9 - ans[i];
             }
             ans[i] += 1;
             while(ans[i] > 9){
                 ans[i + 1] += 1;
                 ans[i] %= 10;
                 i++;
             }
             break;
        }
    }
    cout << buff;
    for(int i = n - 1; i >= 0; i--){
        if(ans[i] == 0 && i > 0){
            continue;
        }
        cout << ans[i];
        while(i){
            i--;
            cout << ans[i];
        }
        return 0;
    }

}