#include <iostream>
#include <vector>
#include <cstdlib>

using namespace std;

int main() 
{
	long long int n;
	cin >> n;
	long long int c = n - 1;
	std::vector<double> A(c), B(c), C(c);	
	for (long long int i = 0; i < c; i++) {
	    A[i] = ((double) rand() / (double) (RAND_MAX));
	    B[i] = ((double) rand() / (double) (RAND_MAX));
	    C[i] = (double) A[i] * B[i];
	    std::cout << i << "   " <<  C[i] << "\n";
	}
	double sum = 0;
	for (long long int i = 0; i < c; i++){
	    sum += C[i];
	}
	std::cout << sum;
	return 0;
}