How could I get this if statement to work right?

For my program, I would like something that asks for the number of students, asks for their scores and then display an output of how many of those scores were A's,B's,C's,etc. So if i input 5 students, I should be able to enter those 5 scores and THEN it'll display the corresponding grades. Instead, it displays the corresponding grades after inputting one score and then asks for another score.

//Declarations
    int A=0,B=0,C=0,D=0,F=0, score,I, students;
    I=1;

    System.out.println("How many students are in your class: ");
    students = input.nextInt();
    while (I<=students) {
    System.out.println("enter a score:");
    score=input.nextInt();


    if(score >= 90 && score <= 100)
        A++;
    else if(score>=80 && score<=89)
        B++;
    else if(score>=70 && score<=79)
        C++;
    else if(score>=60 && score<=69)
        D++;
    else if(score>=0 && score<=59)
        F++;


       System.out.println("Total number of A's:"+ A);
       System.out.println("Total number of B's:"+ B);
       System.out.println("Total number of C's:"+ C);
       System.out.println("Total number of D's:"+ D);
       System.out.println("Total number of F's:"+ F);


}

}}