#include "bits/stdc++.h" using namespace std; /* macro */ #define rep(i,a,b) for(int i=a;i b; i--) #define int long long #define exist(s,e) ((s).find(e)!=(s).end()) #define all(v) (v).begin(), (v).end() #define each(s,itr) for(auto (itr) = s.begin(); (itr) != s.end(); (itr)++) #define sum(v) accumulate(all(v), (0LL)) #define isin(a, b, c) (b <= a && a <= c) #define println cout << "\n"; #define sz(v) (int)v.size() #define bin(x) static_cast >(x) /* alias */ template using vec = vector; typedef vector vi; typedef pair pi; typedef tuple ti; typedef map mi; typedef set si; /* constant */ const int inf = 1LL << 62; const int mod = 1e9 + 7; const int dx[8]={1,0,-1,0,-1,1,-1,1}; const int dy[8]={0,1,0,-1,-1,-1,1,1}; const string alphabet = "abcdefghijklmnopqrstuvwxyz"; /* io_method */ int input(){int tmp;cin >> tmp;return tmp;} string raw_input(){string tmp;cin >> tmp;return tmp;} template void printx(T n){cout << n;} template void printx(pair p){cout << "(" << p.first << "," << p.second << ")";} template void printx(tuple t){cout << "{" << get<0>(t) << "," << get<1>(t) <<"," << get<2>(t) << "}" << endl;} template void printx(vector v){cout << "{";rep(i,0,v.size()){printx(v[i]);if(i != v.size()-1)printx(",");}cout << "}";} template void print(T n){printx(n);cout << endl;} template void print(set s){cout << "{";each(s, e){if(e != s.begin()) printx(",");printx(*e);}cout << "}" << endl;} template void print(map mp){cout << "{";each(mp, e){cout << "(" << e -> first << "," << e -> second << ")";}cout << "}" << endl;} template void printans(vec v){rep(i,0,sz(v)){cout << v[i] << (i == sz(v) - 1 ? "" : " ");}cout << endl;} /* general_method */ templatebool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (bT cut(T &a, int l, int r){return T(a.begin()+l, a.begin()+r);} /* main */ int a, b, c; void in(){ cin >> a >> b >> c; } int ceil(int n, int m){ return n / m + (n % m == 0 ? 0 : 1); } double dp[10010][10010]; double dfs(int rest, int miss){ if(rest < 1) return 0; if(miss < 0) return inf; if(dp[rest][miss] > -1) return dp[rest][miss]; double ans = inf; chmin(ans, 1.0 + dfs(rest - b, miss)); chmin(ans, ((1.0 + dfs(rest - c, miss)) * 2.0 / 3.0) + ((1.0 + dfs(rest,miss -1)) / 3.0)); return dp[rest][miss] = ans; } void solve(){ memset(dp, -1, sizeof(dp)); print(dfs(a, ceil(a / b))); } signed main(){ cin.tie(0); ios::sync_with_stdio(false); in(); solve(); }