 The rule numbers that will then have been written to the output stream will be [5, 3, 5, 2] which is indeed a rightmost derivation of the string "1 + 1" in reverse.The construction of these parsing tables is based on the notion of "LR(0) items" (simply called "items" here) which are grammar rules with a special dot added somewhere in the right-hand side.For example, the rule E → E + B has the following four corresponding items