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

int main() {
	vector<int> A(13);
	for (int i = 0; i < 13; i++) {
		cin >> A[i];
	}
	vector<int> cnt(10);
	for (int i = 0; i < 13; i++) {
		cnt[A[i]]++;
	}
	vector<vector<int>> cnt_d(4);
	for (int i = 1; i <= 9; i++) {
		if (cnt[i] <= 3) {
			cnt_d[cnt[i]].push_back(i);
		}
	}
	if (cnt_d[3].size() == 4) {
		cout << "1\n" << cnt_d[1][0] << '\n';
	} else if (cnt_d[3].size() == 3 && cnt_d[2].size() == 2) {
		cout << "2\n" << cnt_d[2][0] << ' ' << cnt_d[2][1] << '\n';
	} else {
		cout << "0\n\n";
	}
}