#include <algorithm>
#include <vector>
#include <iostream>
#include <math.h>

using namespace std;

#include "matrix.h"

main ()
{
  Tmatrix m;
  readmatrix(cin,m);
  int n=m.size();
  double h=m[1][0]-m[0][0];
  m[0].push_back(-(3*m[0][1]-4*m[1][1]+m[2][1])/(2*h));
  for (int i=1; i<n-1; i++) {
    m[i].push_back((m[i+1][1]-m[i-1][1])/(2*h));
    m[i].push_back((m[i+1][1]+m[i-1][1]-2*m[i][1])/(h*h));    
  }
  m[n-1].push_back(-(3*m[n-1][1]-4*m[n-2][1]+m[n-3][1])/(2*h));
  cout << m;
}