#include<bits/stdc++.h>
using namespace std;
using ll = long long;
int main(){
    int h,a,d;
    cin>>h>>a>>d;
    vector<double> dp(h+1,1e9);
    dp[0] = 0;
    for(int i = 1;i<=h;i++){
        int j = i - a;
        j = max(0,j);
        dp[i] = 1 + dp[j];
        j = i - d;
        j = max(0,j);
        dp[i] = min(dp[i],1.5+dp[j]);
    }
    cout<<dp[h]<<endl;
}