add_person Alice
add_person Bethany
add_person Chris
add_person Dan
add_person Erica
add_person Fred
add_person Greg

add_friendship Alice Bethany
add_friendship Alice Chris
add_friendship Bethany Erica
add_friendship Chris Alice
add_friendship Chris Fred
add_friendship Dan Fred
add_friendship Erica Bethany
add_friendship Erica Chris
add_friendship Erica Greg
add_friendship Fred Greg
add_friendship Greg Erica

print

remove_person Bethany

print

remove_person Bethany
add_person Greg
add_friendship Greg Erica