#include <vector> #include <list> #include <map> #include <set> #include <deque> #include <stack> #include <bitset> #include <algorithm> #include <functional> #include <numeric> #include <utility> #include <sstream> #include <iostream> #include <iomanip> #include <cstdio> #include <cmath> #include <cstdlib> #include <cctype> #include <string> #include <cstring> #include <ctime> #include <fstream> #include <queue> #include <complex> #define INF 100000000 #define INF_INT_MAX 2147483647 #define INF_LL_MAX 9223372036854775807 #define EPS 1e-10 #define Pi acos(-1) #define LL long long #define ULL unsigned long long using namespace std; int H, A, D; int main(){ cin >> H >> A >> D; double ans = INF; for (int a = 0; a < H / A + 1; a++){ if (H - a*A > 0) ans = min(ans, (double)(a + ((H - a*A) / D + 1) * 1.5)); else ans = min(ans, (double)a); } cout << ans << endl; return 0; }