#include <bits/stdc++.h>
  
using namespace std;
  
#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for(int i=(int)(s-1); i>=(int)(e); i--)
#define pb push_back
#define all(r) r.begin(),r.end()
#define rall(r) r.rbegin(),r.rend()
#define fi first
#define se second
  
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
const int INF = 1e9;
const ll MOD = 1e9 + 7;
double EPS = 1e-8;

using D = double;

const int MAX_N = 1e4+10;

D dp[MAX_N];
bool used[MAX_N];

int H, A, X;

D calc(int h) {
    if(h <= 0) return (D)0.0;
    if(used[h]) return dp[h];
    used[h] = true;
    auto& ret = dp[h];
    return ret = min(calc(h-A)+(D)1.0, calc(h-X)+(D)1.5);
} 

int main(){
    cout << fixed << setprecision(15);
    cin >> H >> A >> X;
    cout << calc(H) << endl;
    return 0;
}