#include <bits/stdc++.h>
#define ft first
#define sc second
#define lb lower_bound
#define ub upper_bound
#define pb push_back
#define pt(sth) cout << sth << "\n"
#define chmax(a, b) {if(a<b) a=b;}
#define chmin(a, b) {if(a>b) a=b;}
#define moC(a, s, b) (a)=((a)s(b)+MOD)%MOD
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
static const ll INF=1e18;
static const ll MAX=1e5+7;
static const ll MOD=1e9+7;


int main(void) {
  ll N;
  cin >> N;
  double p, q;
  cin >> p >> q;
  ll i, j;
  
  double tp=p, tq=q;
  
  for(i=0; i<N-1; i++) {
    double a=tp, b=tq;
    tp=a+p*b*b/(1-a*p);
    tq=b*q/(1-a*p);
  }
  
  printf("%.10f\n", tp);
}