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#include <iostream>
#include <algorithm>

void PrintTree(int ones) {
	std::cout << 2 - std::min(ones, 2) << '\n';
	std::cout << 2 << '\n';
	std::cout << "1 2\n";
}

int main() {
	std::ios_base::sync_with_stdio(false);
	int n;
	std::cin >> n;

	int ones = 0;
	for (int i = 0; i < n; i++) {
		int deg;
		std::cin >> deg;
		if (deg == 1) {
			++ones;
		}
	}
	PrintTree(ones);

	return 0;
}