#include<iostream>
#include <cmath>

using namespace std;

int main(){
  int n;
  printf("sum((-1)^j/j,j=1..n), entrer n pair ");
  cin >> n;
  double x=0.0;
  for (int j=1;j<=n;++j){
    if (j%2)
      x += 1.0/j;
    else
      x -= 1.0/j;
  }
  printf("Croissant:           %.16g\n",x);
  x=0.0;
  for (int j=n;j>0;--j){
    if (j%2)
      x += 1.0/j;
    else
      x -= 1.0/j;
  }
  printf("Decroissant:         %.16g\n",x);
  printf("ln(2)-1/2/n+1/4/n^2: %.16g\n",std::log(double(2))-1/double(2)/n+(1/double(4)/n)/n);
}