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



if(marks>90){
    console.log("AA")
}
if(marks>80 && marks<=90){
    console.log("AB")
}
if(marks>80 && marks<=90){
    console.log("BB")
}
if(marks>70 && marks<=80){
    console.log("BC")
}
if(marks>60 && marks<=70){
    console.log("CC")
}

if(marks>50 && marks<=60){
    console.log("CD")
}

if(marks>40 && marks<=50){
    console.log("DD")
}



if(marks<30) {
    console.log("FF")
}