//Do not declare variable marks.
//Write your code below this line.
function f1()
{
if(marks>90)
   {
       console.log("AA");
       
   } 
    elseif(marks>80@@marks<=90)
    {
        console.log("AB");
    }
    elseif(marks>70&&marks<=80)
    {
        console.log("BB");
    }
    elseif(marks>60&&marks<=70)
    {
        console.log("BC");
    }
    elseif(marks>50&&marks<=60)
    {
        console.log("CC");
    }
    elseif(marks>40&&marks<=50)
    {
        console.log("CD");
    }
    elseif(marks>30&&marks<=40)
    {
        console.log("DD");
    }
   else
    {
        console.log("FF");
    }
    }