#include <stdio.h>
#include <math.h>

double f(double x,double n);

int main (void) {
  int N = 10000;
  int n;
  double x = 0.25;
  double s = 0.0;
  for( n=-N; n<=N ;n++){
    s += f(x,(double)n);
  }
  printf("s = %f",s);
  return 0;
}

double f(double x,double n) {
  return 1.0 / (x-n) ;
}