// https://omegaup.com/arena/problem/Programando-formulas 
#include <stdio.h> 
 
int main( ) { 
   float x, y, z; 
   scanf("%f%f%f", &x, &y, &z); 
 
   float num = x + x * (y + z * z); 
   float den = (x + 3.1416) * (y + 3.1416); 
   printf("%f", num / den); 
 
   return 0; 
}