//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");