#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;
	dp[0] = 0;
	rep(i, d+1, 10002) {
		dp[i] = min(dp[max(0,i - a)] + 1, dp[max(0, i - d)] + 1.5);
	}
	print(dp[h]);
	return 0;
}