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#include <iostream>
#include <vector>

int main () {
    int n, cnt = 0, x; std::cin >> n;
    while (n--) {
        std::cin >> x;
        if (x == 1)
            cnt++;
    }
    if (cnt >= 2) 
        std::cout << 0 << std::endl;
    else if (cnt == 1) 
        std::cout << 1 << std::endl;
    else if (cnt == 0) 
        std::cout << 2 << std::endl;
    
    std::cout << 2 << std::endl;
    std::cout << "1 2" << std::endl;
    return 0;
}