#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>

using namespace std;

vector<long double> ans;

long long H, A, D;

long double f(long long n){
    if (n <= 0) return 0;
    if (ans[n] != -1) return ans[n];
    return ans[n] = min(f(n-A)+1, f(n-D)+1.5);
}

int main(){

    cin >> H >> A >> D;
    ans.resize(H+1, -1);

    cout << f(H) << endl;

    return 0;
}