Problem analysis and algorithm design (i.e.: flowchart, algorithm)

import java.util.Scanner;

public class StudentMarks {

    double totalMarks;
    String grade;

    public void setTotalMarks(double totalMarks) {
        this.totalMarks = totalMarks;
    }

    public double getTotalMarks() {
        return totalMarks;
    }

    public void setGrade(String grade) {
        this.grade = grade;
    }

    public String getGrade() {
        return grade;
    }

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter number of students: ");
        int num = input.nextInt();
        StudentMarks data[] = new StudentMarks[num];
        for (int i = 0; i < data.length; i++) {
            System.out.println("Enter marks");
            double marks = input.nextDouble();
            data[i] = new StudentMarks();
            data[i].setTotalMarks(marks);
            if (marks < 40) {
                data[i].setGrade("E");
            }
            if (marks >= 40 && marks <= 44) {
                data[i].setGrade("D");
            }
            if (marks >= 45 && marks <= 49) {
                data[i].setGrade("D+");
            }
            if (marks >= 50 && marks <= 54) {
                data[i].setGrade("C-");
            }
            if (marks >= 55 && marks <= 59) {
                data[i].setGrade("C");
            }
            if (marks >= 60 && marks <= 64) {
                data[i].setGrade("C+");
            }
            if (marks >= 65 && marks <= 69) {
                data[i].setGrade("B-");
            }
            if (marks >= 70 && marks <= 74) {
                data[i].setGrade("B");
            }
            if (marks >= 75 && marks <= 79) {
                data[i].setGrade("B+");
            }
            if (marks >= 80 && marks <= 84) {
                data[i].setGrade("A");
            }
            if (marks >= 85 && marks <= 100)
                data[i].setGrade("A+");
        }

        int count1 = 0;
        int count2 = 0;
        int count3 = 0;
        int count4 = 0;
        for (int i = 0; i < num; i++) {
            StudentMarks show = data[i];
            String g = show.getGrade();
            if (g.equals("A+")) {
                count1++;
            }
            if (g.equals("A")) {
                count2++;
            }
            if (g.equals("D")) {
                count3++;
            }
            if (g.equals("E")) {
                count4++;
            }
        }
        System.out.println("Number of student getting A and A+ grade: "
                + (count1 + count2));
        System.out.println("Number of student getting D and E grade: "
                + (count3 + count4));
    }
}