Problem with if/else statements in C

I'm experiencing some issues with my if / else structure. So, for "num = 65279," I'm not sure why my if / else structure ends up in the first if, as intended, but also in the last if ("f(num = 65535"). I'm not sure why this is occurring, butilized correctly utilised the. How can I improve the structutilizedy code so that this mistake does not occur again? Or what am I doing to cause toccurrror? The value of num is anunsigned short. I'm working with the Lian unsignedmpiler.

if(num >= 55296 && num < 56320){
        ...
}
else{
    if(num <= 127){
                ...
    }
    else{
        if(num <= 2047){
                ...
        }
        else{
            if(num <= 65535){   ...
            }
        }
    }
}