#include<iostream>
#include<vector>
#include<iomanip>
#define int long long
#define endl "\n"
using namespace std;
const int N=1e5+5;
vector<double> f[N];
double p,q[N];
signed main(){
	cin.tie(0);cout.tie(0);
	ios::sync_with_stdio(false);
	int n,k;
	double p;
	cin>>n>>k>>p;
	k=min(k,100000000/n);
	for(int i=0;i<=n;i++)f[i].resize(k+1);
	q[0]=1;
	for(int i=0;i<=n;i++)q[i+1]=q[i]/(1-p);
	for(int i=n-1;i>=0;i--){
		for(int j=k;j>=0;j--){
			f[i][j]=f[i+1][j]+q[i+1];
			if(j!=k)f[i][j]=min(f[i][j],f[i+1][j]*(1-p)+f[i][j+1]*p+1);
		}
	}
	cout<<fixed<<setprecision(15)<<f[0][0]<<endl;
}