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

long state = 7;
long lcg() {
  state = (1103515245L * state + 12345L) % 2147483648L;
  return state;
}
double uniform() { return (double)lcg() / 2147483648.0; }

int main() {
  int n = 20000;
  int hits = 0;
  for (int i = 0; i < n; i++) {
    double x = uniform();
    double y = uniform();
    if (x * x + y * y <= 1.0) hits++;
  }
  double pi = 4.0 * hits / n;
  printf("pi ~ %.4f\n", pi);
  return 0;
}