#include "bits/stdc++.h"
#define ALL(obj) (obj).begin(),(obj).end()
#define RALL(obj) (obj).rbegin(),(obj).rend()
#define REP(i, n) for(int i = 0; i < (int)(n); i++)
#define REPR(i, n) for(int i = (int)(n); i >= 0; i--)
#define FOR(i,n,m) for(int i = (int)(n); i < int(m); i++)
using namespace std;
typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = MOD - 1;
const ll LLINF = 4e18;

int main() {
    int h, a, d; cin >> h >> a >> d;
    vector<double> dp(h + 1,100000.0);
    dp[0] = 0;
    REP(i, h + 1) {
        if (i > a) {
            dp[i] = min(dp[i], dp[i - a] + 1);
        }
        else {
            dp[i] = min(dp[i],1.0);
        }
        if (i > d) {
            dp[i] = min(dp[i], dp[i - d] + 1.5);
        }
        else {
            dp[i] = min(dp[i],1.5);
        }
    }
    cout << dp[h] << endl;
    getchar(); getchar();
}