#include <vector>
#include <iostream>
using namespace std;
vector<int> difference(int *a, int n, int *b, int m){
    vector<int> answer;
    int j = 0;
    for(int i = 0; i < n; i++){
        while(j < m && b[j] < a[i]){
            j++;
        }
        if(j < m && a[i] == b[j]){
            continue;
        }
        answer.push_back(a[i]);
    }
    return answer;
}
int main(){
    int n;
    cin >> n;
    int *a = new int[n];
    for(int i=0;i<n;i++){
        cin >> a[i];
    }
    int m;
    cin >> m;
    int *b = new int[m];
    for(int i=0;i<n;i++){
        cin >> b[i];
    }
    vector <int> answer;
    answer = differ(a,n,b,m);

    cout << answer.size() << endl;
    for(int i = 0; i < answer.size(); i ++){
        cout << it << " ";
    }
    return 0;
}