cat $* | 
nawk '
    /^IMAGE:/ {
	image++
	next
    }

    /^N:[ 	]*\+/ {
	name=$0
	valid++
	printed=0
	next
    }

    /^$/ {
	if (!printed && valid && !image) {
	    print "" name
	    printed=1
	} else if(!printed && valid && image) {
	    print "+" name
	    printed=1
	}
	image=0
	valid=0
	next
    }
    
    // {
	next
    }

'