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#include <iostream>
#include <vector>
#include <algorithm>



int main() {
    int n;
    std::cin >> n;
    
    std::vector<int> nums(n);
    for (int i = 0; i < n; i++) {
        std::cin >> nums[i];
    }
    
    int count = 0;

    for (int i = 1; i <= n; i++) {
        nums.push_back((i * (i + 1)) / 2);
    }
    
    std::sort(nums.begin(), nums.end());

    for (int i = 0; i < nums.size(); i++) {
        std::cout << nums[i] << " ";
    }
    std::cout << std::endl;

    for (int i = 0; i < n - 2; i++) {
        int a = nums[i];
        int start = i + 1;
        int end = n - 1;
        
        while (start < end) {
            int b = nums[start];
            int c = nums[end];
            
            if (a + b + c == 0) {
                std::cout << a << " " << b << " " << c << std::endl;
                count++;
                start = start + 1;
                end = end - 1;
            } else if (a + b + c > 0) {
                end = end - 1;
            } else {
                start = start + 1;
            }
        }
    }



    std::cout << count << std::endl;
    
    return 0;
}