#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <numeric>
#include <cctype>
#include <tuple>
#include <climits>
#include <bitset>
#include <cassert>
#include <random>

#ifdef _MSC_VER
#include <agents.h>
#endif

#define FOR(i, a, b) for(int i = (a); i < (int)(b); ++i)
#define rep(i, n) FOR(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define REV(v) v.rbegin(), v.rend()
#define MEMSET(v, s) memset(v, s, sizeof(v))
#define UNIQUE(v) (v).erase(unique(ALL(v)), (v).end())
#define MP make_pair
#define MT make_tuple

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

const int N = 10010;
double dp[N];

int a, d;

double rec(int h){
	if (h <= 0) return 0;

	double &res = dp[h];
	if (res > -.5) return res;

	res = 1e9;
	res = min(res, 1 + rec(h - a));
	res = min(res, 3./2 + rec(h - d));

	return res;
}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	rep(i, N) dp[i] = -1;
	int h;
	cin >> h >> a >> d;
	cout.setf(ios::fixed);
	cout.precision(11);
	cout << rec(h) << endl;

	return 0;
}