#include <bits/stdc++.h>
using namespace std;

#define vi vector<int>
#define ff first
#define ss second
#define pb push_back
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define ps(x) fixed << setprecision(10) << x
#define mod 1000000007
#define inf 1e18
#define w(tc)  int tc; cin >> tc; for (int i = 1; i <= tc; ++i)
#define PI 3.14159265358979323846264338327950L
#define span(a) begin(a), end(a)
#define ll long long

const int N = 109;
double dp[N][N][N];

double calc(int a, int b, int c) {
	if (a >= 100 or b >= 100 or c >= 100)
		return 0;

	if (dp[a][b][c] >= 0) return dp[a][b][c];

	double tot = a + b + c;
	dp[a][b][c] = 1 + a / tot * calc(a + 1, b, c) + b / tot * calc(a, b + 1, c) + c / tot * calc(a, b, c + 1);

	return dp[a][b][c];
}

inline void solve() {
	memset(dp, -1, sizeof(dp));
	int a, b, c; cin >> a >> b >> c;
	double ans = calc(a, b, c);
	cout << ps(ans);
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	//w(tc)
	solve();
	return 0;
}
#include<bits/stdc++.h>
#define rep(i,a,...) for(int i = (a)*(strlen(#__VA_ARGS__)!=0);i<(int)(strlen(#__VA_ARGS__)?__VA_ARGS__:(a));++i)
#define per(i,a,...) for(int i = (strlen(#__VA_ARGS__)?__VA_ARGS__:(a))-1;i>=(int)(strlen(#__VA_ARGS__)?(a):0);--i)
#define foreach(i, n) for(auto &i:(n))
#define all(x) (x).begin(), (x).end()
#define bit(x) (1ll << (x))
#define lambda(RES_TYPE, ...) (function<RES_TYPE(__VA_ARGS__)>)[&](__VA_ARGS__) -> RES_TYPE
#define method(FUNC_NAME, RES_TYPE, ...) function<RES_TYPE(__VA_ARGS__)> FUNC_NAME = lambda(RES_TYPE, __VA_ARGS__)
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
//const ll MOD = (ll)1e9+7;
const ll MOD = 998244353;
const int INF = (ll)1e9+7;
const ll INFLL = (ll)1e18;
template<class t>
using vvector = vector<vector<t>>;
template<class t>
using vvvector = vector<vector<vector<t>>>;
template<class t>
using priority_queuer = priority_queue<t, vector<t>, greater<t>>;
template<class t, class u> bool chmax(t &a, u b){if(a<b){a=b;return true;}return false;}
template<class t, class u> bool chmin(t &a, u b){if(a>b){a=b;return true;}return false;}
#ifdef DEBUG
#define debug(x) cout<<"LINE "<<__LINE__<<": "<<#x<<" = "<<x<<endl;
#else
#define debug(x) (void)0
#endif

namespace templates{
  ll modpow(ll x, ll b){
    ll res = 1;
    while(b){
      if(b&1)res = res * x % MOD;
      x = x * x % MOD;
      b>>=1;
    }
    return res;
  }

  ll modinv(ll x){
    return modpow(x, MOD-2);
  }

  bool was_output = false;
  template<class t>
  void output(t a){
    if(was_output)cout << " ";
    cout << a;
    was_output = true;
  }
  void outendl(){
    was_output = false;
    cout << endl;
  }
  ll in(){
    ll res;
    cin >> res;
    return res;
  }

  template<class t>
  istream& operator>>(istream&is, vector<t>&x){
    for(auto &i:x)is >> i;
    return is;
  }

  template<class t, class u>
  istream& operator>>(istream&is, pair<t, u>&x){
    is >> x.first >> x.second;
    return is;
  }

  template<class t>
  t in(){
    t res; cin >> res; return res;
  }

  template<class t>
  void out(t x){
    cout << x;
  }

  template<class t>
  vector<t> sorted(vector<t> line,function<bool(t,t)> comp=[](t a,t b){return a<b;}){
    sort(line.begin(),line.end(),comp);
    return line;
  }

  template<class t>
  vector<t> reversed(vector<t> line){
    reverse(line.begin(),line.end());
    return line;
  }
}

using namespace templates;

double func(){
    int a = in();
    int b = in();
    int c = in();
    method(toint,int,int a,int b,int c){
        return c + 101 * (b + 101 * a);
    };
    vector<double> dp(toint(100,100,100),-1);
    method(func,double,int a,int b,int c){
        if(max({a,b,c})==100){
            return 0;
        }
        double &it = dp[toint(a,b,c)];
        if(it>=0)return it;
        it = 0;
        it += (func(a+1,b,c) + 1) * a / (a + b + c);
        it += (func(a,b+1,c) + 1) * b / (a + b + c);
        it += (func(a,b,c+1) + 1) * c / (a + b + c);
        return it;
    };
    return func(a,b,c);
}

int main(){
    printf("%.20lf\n",func());
  return 0;
}
