//Do not declare variable marks.
//Write your code below this line.
var marks = 100;

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