#include <iostream>
#include <vector>
#include <cstdlib>
#include <algorithm>
#include <numeric>

int main()
{
	long long int n;
	std::cin >> n;
	long long int c = n - 1;
	std::vector<double> C(c);
	std::generate(C.begin(), C.end(), []
	{ return (double)rand() / (double)(RAND_MAX) *
		(double)rand() / (double)(RAND_MAX);  });
	long long int i = 0;
	for (auto val : C)
	{
		std::cout << i << "   " << val << "\n";
		++i;
	}
	double sum = std::accumulate(C.begin(), C.end(), 0.0);
	std::cout << sum;
	return 0;
}