#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <string>
#include <numeric>
#include <cstring>
#include <cmath>
#include <set>
#include <queue>
#include <stack>

const int MOD = 1e9 + 7;
const int iINF = 1000000000;
const long long int llINF = 1000000000000000000;
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;
using ll = long long int;
using P = pair<int, int>;
using edge = struct
{
    int to;
    int cost;
};

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

double dp[10010];

int main()
{
    int H, A, D;
    cin >> H >> A >> D;
    rep(i, H + 1) dp[i] = iINF;
    dp[0] = 0;
    for(int i = 1; i <= H; i++)
    {
        dp[i] = min(dp[max(0, i - A)] + 1.0, dp[max(0, i - D)] + 1.5);
    } 

    cout << dp[H] << endl;
    return 0;
}