//Do not declare variable marks.
//Write your code below this line.
great(93);
function great(input){
    if(input>90){
        
        console.log('AA');
        
    }else if(input > 80 && input<90){
        console.log('AB');
        
    }else if(input > 70 && input<80){
        console.log('BB');
        
    }else if(input > 60 && input<70){
        console.log('BC');
        
    }else if(input > 50 && input<60){
        console.log('CC');
        
    }else if(input > 40 && input<50){
        console.log('CD');
        
    }else if(input > 30 && input<40){
        console.log('DD');
        
    }else if(input<30){
        console.log('FF');
        
    }else{
        
        
    }  
    
}