#include <stdio.h>
#include <tgmath.h>
 
// Fortunately, all three functions required in this assignment 
// is one-liner...XD
 
static inline double speed_at_temperature( int temperature );
static inline void instructions( void );
static inline double TRUNC( double digits );
 
int main( void ) {
  
  double given_temp;
  
  instructions();
  scanf( "%lf", &given_temp );
  printf( "Speed is %.2f", TRUNC( speed_at_temperature( given_temp ) ) );
 
  return 0;
}
 
static inline double speed_at_temperature( int temperature ) {
  return 1086.L * sqrt( ( 5.L * temperature + 297.L ) / 247.L );
}
 
static inline void instructions( void ) {
  printf( "please give a number as temperature: " );
}
 
static inline double TRUNC( double digits ) {
  return trunc( 100 * digits ) / 100.L;
}