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

int main(){
	int n = 13;
	vector<int> A(n); for (int& a:A) cin >> a;
	vector<int> R;
	for (int i(1);i < 10;++i){
		A.emplace_back(i);
		vector<int> B(10);
		for (int a:A) ++B[a];
		A.pop_back();
		int x = 0,y = 0;
		for (int a:B) if (a){
			if (a==2) ++x;
			else if (a==3) ++y;
			else x = -1e9;
		}
		if (x==1&&y==4) R.emplace_back(i);
	}
	cout << R.size() << endl;
	for (int a:R) cout << a << ' ';
	cout << endl;
}