/*
10 10 20
38 10 14
49 7 17
10000 10 20
10000 20 10
9987 27 27
8765 345 765
4895 3849 4896
6758 789 1578
9946 13 29
*/

#include <iostream>
#include <string.h>
 
using namespace std;
 
int a,d;
double dp[10001];
 
double e(int h){
  if(h<=0)return 0.;
  if(dp[h]!=0)return dp[h];
  double e1 = e(h-a) + 1.;
  double e2 = e(h-d) + 3./2;
  return dp[h]=min(e1,e2);
}
 
int main(){
  int H,A,D;
  cin >> H >> A >> D;
  a = A;
  d = D;
  memset(dp,0,sizeof(dp));
  cout << e(H) << endl;
  return 0;
}