#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

#define mod 1000003
#define INF 1000000000
#define LLINF 2000000000000000000LL

#define SIZE 10000

int main(){
    int h,a,d;
    int dp[SIZE*2+1],ans=INF;
    
    for(int i=0;i<=SIZE*2;i++) dp[i] = INF;
    
    dp[0] = 0;
    
    scanf("%d%d%d",&h,&a,&d);
    
    for(int i=0;i<h;i++){
        dp[i+a] = min(dp[i+a],dp[i]+2);
        dp[i+d] = min(dp[i+d],dp[i]+3);
        
        if(i+a>=h)
            ans = min(ans,dp[i+a]);
        if(i+d>=h)
            ans = min(ans,dp[i+d]);
    }
    
    printf("%.2lf",ans/2.0);
    
    return 0;
}