OpenBSD-4.6/usr.bin/learn/lib/eqn/L7.2b

#print
Does the input

  sum from {i = -n} to {i = +n}

produce the same output as the input

  sum from i=-n to i=+n

Answer yes or no.
#copyin
#user
#uncopyin
#match yes
#log
#next
7.1c