#include <stdio.h>

int main(void)
{
  int n,g,b;
  int coin;
  double g_out;
  double mitudo;

  scanf("%d",&n);
  scanf("%d",&g);
  scanf("%d",&b);
  //printf("%d %d %d\n", n, g, b);

  coin = n / 5;
  // printf("%d\n", coin);
  g_out =(double) g*coin;
  //printf("%lf\n",g_out);

  mitudo = (double)g_out / b;

  printf("%.12f\n",mitudo);

  return 0;
}