#include <stdio.h>
main(void)
{
  long i,n;
  double a=0, b;
  double sign=1;
  printf("How many iterations?");
  scanf("%d",&n);
  b=1.0/5;
  for (i=1; i<n; i++) {
    a += b / (2*i-1);
    b = -b /(5*5);
  }
  a *= 4;
  b=-1.0/239;
  for (i=1; i<n/3.4; i++) {
    a += b / (2*i-1);
    b = -b /(239*239);
  }
  printf("pi is nearly %.20f\n", 4*a);
}