/*
  a[i] = P b[i - 1] + Q a[i + 1]
  b[i] = P a[i + 1] + Q b[i - 1]
  
  a[N + 1] = 0
  b[0] = 1
*/

import std.conv, std.functional, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.complex, std.container, std.math, std.numeric, std.range, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


int N;
real P, Q;

void main() {
  try {
    for (; ; ) {
      N = readInt();
      P = readReal();
      Q = readReal();
      
      real ans;
      if (Q == 0.0) {
        ans = 1.0;
      } else {
        auto a = new real[][](N + 2, 2);
        auto b = new real[][](N + 2, 2);
        a[1] = [0.0, 1.0];
        b[0] = [1.0, 0.0];
        foreach (i; 1 .. N + 1) {
          // a[i + 1] = (a[i] - P b[i - 1]) / Q
          foreach (d; 0 .. 2) {
            a[i + 1][d] = (a[i][d] - P * b[i - 1][d]) / Q;
          }
          // b[i] = P a[i + 1] + Q b[i - 1]
          foreach (d; 0 .. 2) {
            b[i][d] = P * a[i + 1][d] + Q * b[i - 1][d];
          }
        }
        ans = -a[N + 1][0] / a[N + 1][1];
      }
      writefln("%.20f", ans);
    }
  } catch (EOFException e) {
  }
}