#include <bits/stdc++.h>
typedef long long LL;
const int N = 2e3 + 5; const double EPS = 1e-9, MX = 1e18;
struct Vector {
    double x, y;
    Vector(double x = 0, double y = 0) : x(x), y(y) {}
    Vector operator+(Vector b) const { return Vector(x + b.x, y + b.y); }
    Vector operator-(Vector b) const { return Vector(x - b.x, y - b.y); }
    Vector operator*(double b) const { return Vector(x * b, y * b); }
    friend double dot(Vector a, Vector b) { return a.x * b.x + a.y * b.y; }
    friend double cross(Vector a, Vector b) { return a.x * b.y - a.y * b.x; }
    double length() { return sqrt(x * x + y * y); }
};
struct Line {
    Vector p, d;
    Line(Vector p = Vector(), Vector d = Vector()) : p(p), d(d) {}
};
struct Circle {
    Vector o; double r;
    Circle(Vector o = Vector(), double r = 0) : o(o), r(r) {}
    bool contains(Vector p) { return (p - o).length() < r + EPS; }
};
Vector midpoint(Vector a, Vector b) { return (a + b) * 0.5; }
Vector intersect(Line a, Line b) {
    double t = cross(b.d, a.p - b.p) / cross(a.d, b.d);
    return a.p + a.d * t;
}
Line perpendicularBisector(Vector a, Vector b) {
    return Line((a + b) * 0.5, Vector(a.y - b.y, b.x - a.x));
}
Circle circumCircle(Vector a, Vector b, Vector c) {
    Vector p = intersect(perpendicularBisector(a, b), perpendicularBisector(b, c));
    return Circle(p, (p - a).length());
}
int n, K; LL seed; Vector a[N]; Circle c[N][N]; double f[N][N];
#define calc(x) (LL(x) * 233811181 + 1) % LL(~0u >> 1)
int main() {
    scanf("%d%d%lld", &n, &K, &seed), a[1].x = seed, a[1].y = seed = calc(seed);
    for(int i = 2; i <= n; i++) a[i].x = seed = calc(seed), a[i].y = seed = calc(seed);
    for(int k = 1; k <= K; k++) f[n + 1][k] = MX;
    for(int bg = n; bg; bg--) {
        c[bg][bg] = Circle(a[bg], 0), f[bg][0] = MX;
        for(int k = 0; k <= K; k++) f[bg][k] = MX;
        for(int i = bg + 1; i <= n; i++) {
            c[bg][i] = c[bg][i - 1];
            if(c[bg][i].contains(a[i])) continue;
            for(int k = 1; k <= K; k++) f[bg][k] = std::min(f[bg][k], c[bg][i].r + f[i][k - 1]);
            c[bg][i] = Circle(midpoint(a[i], a[bg]), (a[i] - a[bg]).length() / 2);
            for(int j = bg; j < i; j++) {
                if(c[bg][i].contains(a[j])) continue;
                c[bg][i] = Circle(midpoint(a[i], a[j]), (a[i] - a[j]).length() / 2);
                for(int k = bg; k < j; k++) {
                    if(c[bg][i].contains(a[k])) continue;
                    c[bg][i] = circumCircle(a[i], a[j], a[k]);
                }
            }
        }
        f[bg][1] = c[bg][n].r;
    }
    printf("%.9lf\n", f[1][K]);
    return 0;
}