#include <bits/stdc++.h>
using namespace std;

int f(int x) {
	return (x * 233811181LL + 1) % ((1LL << 31) - 1);
}

using dbl = double;

const dbl INF = 1e30;
const dbl EPS = 1e-8;

class MinimumEnclosingCircle {

	class Circle {
	public:
		dbl x, y, r;
		Circle(dbl x, dbl y, dbl r) : x(x), y(y), r(r) {}
	};

	vector<pair<dbl, dbl>> pt;
	
	inline dbl sqr(dbl x) {
		return x * x;
	}

	dbl sqrDist(dbl x, dbl y) {
		return sqr(x) + sqr(y);
	}

	pair<dbl, dbl> getCenter(dbl ax, dbl ay, dbl bx, dbl by, dbl cx, dbl cy) {
		vector<dbl> x = {ax, bx, cx};
		vector<dbl> y = {ax, bx, cx};
		dbl d = 2 * (ax * (by - cy) + bx * (cy - ay) + cx * (ay - by));
		dbl xx = ((sqr(ax) + sqr(ay)) * (by - cy) + (sqr(bx) + sqr(by)) * (cy - ay) + (sqr(cx) + sqr(cy)) * (ay - by)) / d;
		dbl yy = ((sqr(ax) + sqr(ay)) * (cx - bx) + (sqr(bx) + sqr(by)) * (ax - cx) + (sqr(cx) + sqr(cy)) * (bx - ax)) / d;
		return {xx, yy};
	}

	Circle constructCircle(vector<int> &onBoundary) {
		if (onBoundary.empty()) {
			return Circle(0, 0, 0);
		}
		if (onBoundary.size() == 1) {
			return Circle(pt[onBoundary[0]].first, pt[onBoundary[0]].second, 0);
		}
		if (onBoundary.size() == 2) {
			dbl x = (pt[onBoundary[0]].first + pt[onBoundary[1]].first) * 0.5;
			dbl y = (pt[onBoundary[0]].second + pt[onBoundary[1]].second) * 0.5;
			return Circle(x, y, sqr(x - pt[onBoundary[0]].first) + sqr(y - pt[onBoundary[0]].second));
		}
		auto center = getCenter(pt[onBoundary[0]].first, pt[onBoundary[0]].second, pt[onBoundary[1]].first, pt[onBoundary[1]].second, pt[onBoundary[2]].first, pt[onBoundary[2]].second);
		return Circle(center.first, center.second, sqr(center.first - pt[onBoundary[0]].first) + sqr(center.second - pt[onBoundary[0]].second));
	}

	Circle welzl(vector<int> &forbidden, vector<int> &onBoundary) {
		if (pt.size() == forbidden.size() || onBoundary.size() == 3) {
			return constructCircle(onBoundary);
		}
		int nextForbidden = forbidden.empty() ? 0 : forbidden.back() + 1;
		forbidden.push_back(nextForbidden);
		Circle circle = welzl(forbidden, onBoundary);
		if ((sqr(circle.x - pt[nextForbidden].first) + sqr(circle.y - pt[nextForbidden].second)) <= circle.r) {
			forbidden.pop_back();
			return circle;
		}
		onBoundary.push_back(nextForbidden);
		circle = welzl(forbidden, onBoundary);
		forbidden.pop_back();
		onBoundary.pop_back();
		return circle;
	}

public:
	dbl xc;
	dbl yc;
	dbl rSquared;

	void addPoint(dbl x, dbl y) {
		pt.push_back(make_pair(x, y));
		if (pt.size() == 1) {
			xc = x;
			yc = y;
			rSquared = 0;
			return;
		}
		if (sqrDist(x - xc, y - yc) <= rSquared) {
			return;
		}
		vector<int> forbidden;
		vector<int> onBoundary;
		Circle circle = welzl(forbidden, onBoundary);
		xc = circle.x;
		yc = circle.y;
		rSquared = circle.r;
	}
};

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	int n, k, x1;
	cin >> n >> k >> x1;
	vector<int> x(n);
	vector<int> y(n);
	x[0] = x1;
	y[0] = f(x[0]);
	for (int i = 1; i < n; ++i) {
		x[i] = f(y[i - 1]);
		y[i] = f(x[i]);
	}
	vector<vector<dbl>> mec(n + 1, vector<dbl>(n + 1));
	for (int i = 0; i < n; ++i) {
		MinimumEnclosingCircle m;
		m.addPoint(x[i], y[i]);
		mec[i][i + 1] = 0;
		for (int j = i + 1; j < n; ++j) {
			m.addPoint(x[j], y[j]);
			mec[i][j + 1] = m.rSquared;
		}
	}   
	for (int i = 0; i < (int) mec.size(); ++i) {
		for (int j = i + 1; j < (int) mec.size(); ++j) {
			mec[i][j] = sqrt(mec[i][j]);
		}
	}
	vector<vector<int>> changes(n + 1);
	for (int i = 1; i < (int) mec.size(); ++i) {
		for (int j = i - 2; j >= 0; --j) {
			if (mec[j][i] != mec[j + 1][i]) {
				changes[i].push_back(j + 1);
			}
		}
		changes[i].push_back(0);
	}        
	vector<vector<dbl>> dp(k + 1, vector<dbl>(n + 1, INF));
	dp[0][0] = 0;
	for (int i = 1; i <= k; ++i) {
		for (int j = 1; j <= n; ++j) {
			for (auto change : changes[j]) {
				dp[i][j] = min(dp[i][j], dp[i - 1][change] + mec[change][j]);
			}
		}
	}
	cout.precision(12);
	cout << fixed << showpoint;
	cout << dp[k][n] << '\n';
	return 0;
}