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

int main()
{
  int a,b,c;
  cin >> a >> b >> c;
  int n = 101;
  double e[n][n][n];
  for(int i = 0; i < n; ++i){
    for(int j = 0; j < n; ++j){
      e[i][j][100] = 0;
      e[100][i][j] = 0;
      e[j][100][i] = 0;
    }
  }
  for(int i = n-2; i >= a; --i){
    for(int j = n-2; j >= b; --j){
      for(int k = n-2; k >= c; --k){
        e[i][j][k] = ((double)i*(e[i+1][j][k])
          + (double)j*(e[i][j+1][k])
          + (double)k*(e[i][j][k+1]))/(double)(i+j+k)
          + 1;
      }
    }
  }
  cout << fixed << setprecision(9) <<  e[a][b][c] <<endl;
}

#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i = (a); i < (b); i++)
#define drep(i,b,a) for(int i = (b)-1; i >= (a); i--)
#define bit(n) (1LL << (n))
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define SORT(v) sort(v.begin(),v.end());
#define RSORT(v) sort(v.rbegin(),v.rend());
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<double> vd;
typedef vector<bool> vb;
typedef vector<char> vc;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vd> vvd;
typedef vector<vb> vvb;
typedef vector<vc> vvc;
const int inf = 1 << 30; const ll infl = 1LL << 60; const double PI = acos(-1.0);
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T> inline bool  odd(T x) { return x & 1; }
template<class T> inline bool even(T x) { return !(x & 1); }
template<typename A, size_t N, typename T> 
void Fill(A (&array)[N], const T &val) {
    std::fill( (T*)array, (T*)(array+N), val );
}
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << endl; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, set<T> P)
{ for(auto it : P) { s << "<" << it << "> "; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ for(auto it : P) { s << "<" << it.first << "->" << it.second << "> "; } return s; }
//----------------------------------------------------------------------------------------------

double dpd[101][101];
double dpt[101][101][101];

int main() 
{
    vector<int> v(3);
    rep(i,0,3) cin >> v[i];
    SORT(v);
    if(v[1] == 0) cout << 100-v[2] << endl;
    else if(v[0] == 0) {
        int a = v[1], b = v[2];
        for(int i = 99; i >= a; --i) {
            for(int j = 99; j >= b; --j) {
                dpd[i][j] += (double)i/(double)(i+j) * (dpd[i+1][j] + 1);
                dpd[i][j] += (double)j/(double)(i+j) * (dpd[i][j+1] + 1);
            }
        }
        cout << fixed << setprecision(10) << dpd[a][b] << endl;
    } else {
        int a = v[0], b = v[1], c = v[2];
        for(int i = 99; i >= a; --i) {
            for(int j = 99; j >= b; --j) {
                for(int k = 99; k >= c; --k) {
                    dpt[i][j][k] += (double)i/(double)(i+j+k) * (dpt[i+1][j][k] + 1);
                    dpt[i][j][k] += (double)j/(double)(i+j+k) * (dpt[i][j+1][k] + 1);
                    dpt[i][j][k] += (double)k/(double)(i+j+k) * (dpt[i][j][k+1] + 1);
                }
            }
        }
        cout << fixed << setprecision(10) << dpt[a][b][c] << endl;
    }
    return 0;
}