#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>
#define PI 3.141529
#define NUM 1000000
int main()
{
  int i,j,count;
  float a,b,sum,sum2,y,x;
  srand((unsigned) time(NULL));
  a=0;
  b=PI;
  sum=0;
  for(i=0;i<NUM;i++){
    x=((rand()%100));
    y=(b-a)*sin(x*b/100);
    sum=sum+y;
  }
  sum2=sum/NUM;
  printf("%f\n",sum2);
}