//Do not declare variable marks.
//Write your code below this line.

function sPrint(str){
    console.log(sPrint);
}

if (marks > 90) {
    console.log('AA');
} else if (marks > 80 && marsk <= 90){
    console.log('AB');   
} else if (marks > 70 && marsk <= 80){
    console.log('BB');    
} else if (marks > 60 && marsk <= 70){
    console.log('BC');    
} else if (marks > 50 && marsk <= 60){
    console.log('CC');    
} else if (marks > 40 && marsk <= 50){
    console.log('CD');    
} else if (marks > 30 && marsk <= 40){
    console.log('DD');    
} else {
    console.log('FF');    
}