find the integer multiple of 3 whose square is closest to but lower than or equal to a number entered by the user. Replace lines 5-11, use a while loop but I'm not meant to use 'if' or 'floor'

clear
value=input('Enter a number ');
for i = 1:value    
    if rem(i,3) == 0 && i*i <= value        
        j=i;    
    else
        break;    
    end
end
fprintf('The integer multiple of 3 that is less than or equal to the square root of%f is %d\n', ...         
    value, j);