---

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        double x = sc.nextDouble();
        double h = sc.nextDouble();
        double a = sc.nextDouble();

        double[] R = new double[n];

        for (int i = 0; i < n; i++) {
            int j = i + 1;
            R[i] = 2.5 * Math.sin(a * x + j * j * h);
        }

        System.out.print("R={");
        for (int i = 0; i < n; i++) {
            System.out.printf("%.3f", R[i]);
            if (i < n - 1) {
                System.out.print("; ");
            }
        }
        System.out.println("}");
    }
}




import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        double x = sc.nextDouble();
        double h = sc.nextDouble();
        double a = sc.nextDouble();

        double[] R = new double[n];

        for (int i = 0; i < n; i++) {
            int j = i + 1;
            R[i] = 2.5 * Math.sin(a * x + j * j * h);
        }

        int minIndex = 0;

        for (int i = 1; i < n; i++) {
            if (R[i] < R[minIndex]) {
                minIndex = i;
            }
        }

        int posIndex = -1;

        for (int i = 0; i < n; i++) {
            if (R[i] > 0) {
                posIndex = i;
            }
        }

        if (posIndex == -1) {
            System.out.println("Нет положительного элемента");
        } else {
            int left = Math.min(minIndex, posIndex);
            int right = Math.max(minIndex, posIndex);

            for (int i = left + 1; i < right; i++) {
                if (R[i] < 0) {
                    for (int j = i; j < n - 1; j++) {
                        R[j] = R[j + 1];
                    }
                    n--;
                    i--;
                    right--;
                }
            }
        }

        System.out.print("R={");
        for (int i = 0; i < n; i++) {
            System.out.printf("%.3f", R[i]);
            if (i < n - 1) {
                System.out.print("; ");
            }
        }
        System.out.println("}");
    }
}



import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        double x = sc.nextDouble();
        double h = sc.nextDouble();
        double a = sc.nextDouble();

        double[] R = new double[n];

        for (int i = 0; i < n; i++) {
            int j = i + 1;
            R[i] = 2.5 * Math.sin(a * x + j * j * h);
        }

        // Поиск первого минимума
        int minIndex = 0;
        for (int i = 1; i < n; i++) {
            if (R[i] < R[minIndex]) {
                minIndex = i;
            }
        }

        // Поиск последнего положительного
        int posIndex = -1;
        for (int i = 0; i < n; i++) {
            if (R[i] > 0) {
                posIndex = i;
            }
        }

        // Удаление отрицательных
        if (posIndex != -1) {
            int left = Math.min(minIndex, posIndex);
            int right = Math.max(minIndex, posIndex);

            for (int i = left + 1; i < right; i++) {
                if (R[i] < 0) {
                    for (int j = i; j < n - 1; j++) {
                        R[j] = R[j + 1];
                    }
                    n--;
                    i--;
                    right--;
                }
            }
        }

        // Вычисление среднего
        double sum = 0;
        int count = 0;
        boolean found = false;

        for (int i = 0; i < n; i++) {
            if (R[i] < 0) {
                found = true;
                break;
            }

            sum += R[i];
            count++;
        }

        if (!found || count == 0) {
            System.out.println("Нет среднего значения");
        } else {
            double sr = sum / count;
            System.out.printf("Sr=%.3f%n", sr);
        }
    }
}