#include <bits/stdc++.h>
using namespace std;
using ll = long long;

template<class T> istream& operator >> (istream& is, vector<T>& vec) {
    for(T& x : vec) is >> x;
    return is;
}

template<class T> ostream& operator << (ostream& os, const vector<T>& vec) {
    if(vec.empty()) return os;
    os << vec[0];
    for(auto it = vec.begin(); ++it != vec.end(); ) os << ' ' << *it;
    return os;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    array<int, 10> cnt{}, ary;
    fill(ary.begin(), ary.end(), 0);
    ary[2] = 2;
    ary[3] = 4;
    vector<int> b(13);
    for(auto &&v : b) cin >> v;
    sort(b.begin(), b.end());
    for(int i = 0; i < 13; ){
        int p = i;
        while(i < 13 && b[i] == b[p]) i++;
        cnt[i - p]++;
    } 
    vector<int> ans;
    for(int i = 1; i <= 9; i++){
        cnt[i]++;
        if(cnt == ary) ans.push_back(i);
        cnt[i]--;
    }
    cout << ans.size() << '\n';
    cout << ans << '\n';
}