//Do not declare variable marks.
//Write your code below this line.
if (marks > 90){
console.log("AA");}
else if (marks > 80 && <= 90){
console.log("AB");}
else if (marks > 70 && <=80){
console.log( "BB");}
else if (marks > 60 && <=70){
console.log("BC");}
else if (marks > 50 && <=60){
console.log("CC");}
else if (marks > 40 && <=50){
console.log("CD");}
else if (marks > 30 && <=40){
console.log("DD");}
else (marks <= 30){
console.log("FF");}