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

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