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

double a[30010];
int main()
{
    const double inf=1e5;
    double* E=a+1001;
    int H, A, D;
    while (cin>>H>>A>>D) {
        fill(E, E+H+max(A, D)+1, inf);
        E[0]=0;
        for(int i=0;i<=H;++i) {
           E[i+A]=min(E[i+A], E[i]+1);
           E[i+D]=min(E[i+D], E[i]+1.5);
        }
        double res=inf;
        for(int i=H;i<=H+max(A,D);++i) if (E[i]>0) res=min(res, E[i]);
        cout<<res<<endl;
    }
}