#include"bits/stdc++.h"

//#include<bits/stdc++.h>
using namespace std;
#define print(x) cout<<x<<endl;
#define rep(i,a,b) for(int i=a;i<b;i++)
typedef long long ll;
const ll mod = 10000000000;

int main(){
	int h, a, d;
	double dp[10002];
	memset(dp, -1, sizeof(dp));
	cin >> h >> a >> d;
	double aa = 0;
	if (h%a == 0)aa = h / a;
	else { aa = h / a + 1; }
	double dd = 0;
	if (h%d == 0)dd = h / d;
	else {
		if (h - h / d*d < a) { dd = h / d*1.5 + 1; }
		else { dd = h / d + 1; dd *= 1.5; }
	}
	double ans = min(aa, dd);
	print(ans);
}