//C
#include <bits/stdc++.h>

using namespace std;

#define INF 100000000
#define YJ 1145141919
#define INF_INT_MAX 2147483647
#define INF_LL 9223372036854775
#define INF_LL_MAX 9223372036854775807
#define EPS 1e-10
#define MOD 1000000007
#define MOD9 998244353
#define Pi acos(-1)
#define LL long long
#define ULL unsigned long long
#define LD long double

#define int long long

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(a)  begin((a)), end((a))
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())

const int MAX_H = 10005;
int H, A, D;

double dp[MAX_H];

signed main()
{
  cin >> H >> A >> D;
  REP(h,H+1) {
    dp[h] = INF_INT_MAX;
  }
  dp[H] = 0;

  for(int h = H; 0 <= h; h--) {
    dp[max((LL)0,h-A)] = min(dp[max((LL)0,h-A)], dp[h]+1);
    dp[max((LL)0,h-D)] = min(dp[max((LL)0,h-D)], dp[h]+1.5);
  }

  cout << dp[0] << endl;

  return 0;
}