'else' without 'if' despite use of braces

I've been getting the 'else' without 'if' error for the following code and I'm not sure why. I've used braces and everything so I'm really confused.

        if(mean >= 90 && mean <= 100){
            grade = 'O';}

        else{ 
            if(mean >= 80 && mean < 90)
            grade = 'E';}

        else{ 
            if(mean >= 70 && mean < 80)
            grade = 'A';}

        else{ 
            if(mean >= 55 && mean < 70)
            grade = 'P';}

        else{ 
            if(mean >= 40 && mean < 55)
            grade = 'D';}

        else{ 
            if(mean < 40)
            grade = 'T';}