#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }


using Double = long double;

const Double EPS = 1e-10L;
const Double INF = 1e+10L;
const Double PI = acos(-1.0L);
inline int sig(Double r) { return (r < -EPS) ? -1 : (r > +EPS) ? +1 : 0; }

struct Pt {
  Double x, y;
  Pt() {}
  Pt(Double x_, Double y_) : x(x_), y(y_) {}
  Pt operator+(const Pt &a) const { return Pt(x + a.x, y + a.y); }
  Pt operator-(const Pt &a) const { return Pt(x - a.x, y - a.y); }
  Pt operator*(const Pt &a) const { return Pt(x * a.x - y * a.y, x * a.y + y * a.x); }
  Pt operator/(const Pt &a) const { const Double d2 = a.abs2(); return Pt((x * a.x + y * a.y) / d2, (y * a.x - x * a.y) / d2); }
  Pt operator+() const { return Pt(+x, +y); }
  Pt operator-() const { return Pt(-x, -y); }
  Pt operator*(const Double &k) const { return Pt(x * k, y * k); }
  Pt operator/(const Double &k) const { return Pt(x / k, y / k); }
  friend Pt operator*(const Double &k, const Pt &a) { return Pt(k * a.x, k * a.y); }
  Pt &operator+=(const Pt &a) { x += a.x; y += a.y; return *this; }
  Pt &operator-=(const Pt &a) { x -= a.x; y -= a.y; return *this; }
  Pt &operator*=(const Pt &a) { return *this = *this * a; }
  Pt &operator/=(const Pt &a) { return *this = *this / a; }
  Pt &operator*=(const Double &k) { x *= k; y *= k; return *this; }
  Pt &operator/=(const Double &k) { x /= k; y /= k; return *this; }
  Double abs() const { return sqrt(x * x + y * y); }
  Double abs2() const { return x * x + y * y; }
  Double arg() const { return atan2(y, x); }
  Double dot(const Pt &a) const { return x * a.x + y * a.y; }
  Double det(const Pt &a) const { return x * a.y - y * a.x; }
  friend ostream &operator<<(ostream &os, const Pt &a) { os << "(" << a.x << ", " << a.y << ")"; return os; }
};

Pt circumcenter(const Pt &a, const Pt &b, const Pt &c) {
  const Pt bc = c - b, ca = a - c, ab = b - a;
  return (b + c - bc * Pt(0, 1) * ca.dot(ab) / ca.det(ab)) / 2;
}


// r2s[i] := (min radius of circle containing as[0, i))^2
// expected O(|as|) time if shuffled
vector<Double> minCircle(const vector<Pt> &as) {
  const int asLen = as.size();
  vector<Double> r2s(asLen + 1, 0.0);
  if (asLen >= 2) {
    Pt cen;
    Double rad2;
    auto contains = [&](int i) -> bool {
      return ((as[i] - cen).abs2() <= rad2);
    };
    auto build2 = [&](int i, int j) -> void {
      cen = (as[i] + as[j]) / 2.0;
      rad2 = (as[i] - cen).abs2();
    };
    auto build3 = [&](int i, int j, int k) -> void {
      cen = circumcenter(as[i], as[j], as[k]);
      rad2 = (as[i] - cen).abs2();
    };
    build2(0, 1);
    for (int i = 2; ; ++i) {
      r2s[i] = rad2;
      if (i == asLen) break;
      if (!contains(i)) {
        // i must be on the boundary
        build2(i, 0);
        for (int j = 1; j < i; ++j) if (!contains(j)) {
          // j must be on the boundary
          build2(i, j);
          for (int k = 0; k < j; ++k) if (!contains(k)) {
            // k must be on the boundary
            build3(i, j, k);
          }
        }
      }
    }
  }
  return r2s;
}


Int X;
void gen() {
  X = (X * 233811181LL + 1) % ((1LL << 31) - 1);
}

int N, K;
vector<Pt> P;

Double dp[2010][2010];

int main() {
  for (; ~scanf("%d%d%lld", &N, &K, &X); ) {
    P.resize(N);
    for (int i = 0; i < N; ++i) {
      P[i].x = X; gen();
      P[i].y = X; gen();
    }
    
    for (int i = 0; i <= N; ++i) {
      fill(dp[i], dp[i] + (K + 1), INF);
    }
    dp[0][0] = 0.0;
    for (int i = 0; i < N; ++i) {
      const auto r2s = minCircle(vector<Pt>(P.begin() + i, P.end()));
      for (int j = i + 1; j <= N; ++j) {
        if (j == N || r2s[j - i] < r2s[j + 1 - i]) {
          const Double r = sqrt(r2s[j - i]);
          for (int k = 0; k < K; ++k) {
            chmin(dp[j][k + 1], dp[i][k] + r);
          }
        }
      }
    }
    Double ans = INF;
    for (int k = 0; k <= K; ++k) {
      chmin(ans, dp[N][k]);
    }
    printf("%.15Lf\n", ans);
  }
  return 0;
}