#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)
#define INF (int)1e8
#define MOD (int)(1e9+7)

typedef long long ll;

int main(void) {
    int h, a, d;
    cin >> h >> a >> d;
    if (a >= d * 2. / 3)
        cout << (h+a-1) / a << endl;
    else {
        if (h % d <= a)
            cout << h / d * 1.5 + 1 << endl;
        else
            cout << (h+d-1) / d * 1.5 << endl;
    }
    return 0;
}