#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;

typedef pair<double, double> DP;

double p, q;

DP joint(DP dp1, DP dp2) {
  DP res;
  double p1=dp1.ft, q1=dp1.sc;
  double p2=dp2.ft, q2=dp2.sc;
  res.ft=p1+p2*q1*q1/(1-p1*p2);
  res.sc=p2*q1*q2/(1-p1*p2);
  return res;
}

DP dpow(DP dp, ll n) {
  DP res=DP(p, q);
  while(n>0) {
    if(n&1) res=joint(res, dp);
    dp=joint(dp, dp);
    n>>=1;
  }
  return res;
}


int main(void) {
  ll N;
  cin >> N;
  cin >> p >> q;
  ll i, j;
  
  printf("%.10f\n", dpow(DP(p, q), N-1).ft);
}