#include #define rep(i,a,n) for (int i = a; i < n; i++) #define per(i,n,a) for (int i = n - 1; i >= a; i--) using namespace std; double dp[20000]; int main() { int h, a, d; cin >> h >> a >> d; rep(i, 1, h + 1) { dp[i] = min(dp[max(0, i - a)] + 1, dp[max(0, i - d)] + 1.5); } printf("%.1f\n", dp[h]); }