#include<bits/stdc++.h>
#define endl '\n'
typedef long long ll;
using namespace std;
const int N = 1e5 + 5;
int n,k;
typedef double ld;
ld dp[N][205],p,pw[N];
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> k >> p;
	if(k > 180)return cout << n * 1.0 / (1 - p),0;
	pw[0] = 1;
	for(int i = 1;i <= n;i++)pw[i] = pw[i - 1] / (1 - p);
	for(int i = n - 1;i >= 0;i--){
		for(int j = 0;j <= k;j++){
			dp[i][j] = pw[i + 1] + dp[i + 1][j];
			if(j)dp[i][j] = min(dp[i][j],1 + (1 - p) * dp[i + 1][j] + p * dp[i][j - 1]);
		}
	}
	cout << fixed << setprecision(20) << dp[0][k];
}