#define _CRT_RAND_S
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

const double pi = 3.1415926536;;
const double e = 2.7182818285;

double function(double x)
{
 double fout = 1. / sqrt(2 * pi)*pow(e, -x*x);
 return fout;
}

int main()
{
 unsigned int rValue;
 int i;
 double sum = 0.;
 double x;
 double probalility;
 for (i = 0; i < 100000; i++){
  rand_s(&rValue);
  rValue %= 60001;
  x = (signed(rValue) - 30000) / 10000.;
  sum += function(x);
 }

 probalility = sum * 6 / 100000.;
 printf("%lf\n", probalility);

 return 0;
}