// Output a spiked skyline of N buildings.
#include <iostream>
#include <sstream>

bool read_int(char const * arg, int & v)
{
    std::stringstream ss;
    ss << arg;
    ss >> v;
    return ss;
}

int main(int argc, char * argv[])
{
    int errors = 0;
    int N = -1;
    if (argc != 2 || !read_int(argv[1], N) || N < 0)
    {
        ++errors;
        std::cerr << "Usage: " << argv[0] << " N";
    }
    else
    {
        int const H = 100000000;
        int const M = (N + 1) / 2;
        int const h_step = 2 * H / (N + 1);
        int h = 0, i = 0;

        std::cout << N << '\n';

        for (; i != M; i++)
        {
            std::cout << "1000 " << (h += h_step) << "  ";
        }
        for (; i != N; i++)
        {
            std::cout << "1000 " << (h -= h_step) << "  ";
        }
        std::cout << '\n';
    }
    return errors;
}