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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N = 13;
    vector<int> A(N);
    for(auto &a : A) cin >> a;
    vector<int> answer;
    for(int i=1; i<10; i++){
        A.push_back(i);
        map<int,int> M;
        for(auto a : A) M[a]++;
        int two = 0,three = 0;
        for(auto [k,v] : M) two += v==2,three += v==3;
        if(two == 1 && three == 4) answer.push_back(i);
        A.pop_back();
    }
    cout << answer.size() << "\n";
    for(auto a : answer) cout << a << " "; cout << "\n";
}