#include <cstdio>
#include <cstdlib>
#include <ctime>


inline double frand() { return (double)rand() / (double)RAND_MAX; }

int main() {
  
  srand(time(NULL));
  unsigned int N=0, M=0;
  
  for(unsigned int i = 0; i < 100000000; i++) {
    double x = frand(), y = frand();
    if(x*x + y*y < 1.0) M++;
    N++;
  }  
  
  double pi = 4.0 * ((double)M / (double)N);
  
  printf("Pi is %f\n", pi);
  system("PAUSE");
  return 0; 
}