I have a context free grammar (CFG). The initial symbol is `A1`. The terminal symbols are just integers and the non-terminal symbols start with `A`. I also have a target sequence of terminal symbols which needs to be produced by the grammar. However, the CFG production rules have had some terminal symbols removed which may now render it impossible to produce the target sequence. Please attempt to repair the CFG so that the sequence can be produced. The only operations which can be made to repair the CFG are the insertion of terminal symbols anywhere in existing production rules. Deleting or reordering symbols in existing production rules and creating new production rules is prohibited. Please try minimize the total number of terminal symbols inserted into the production rules so that the CFG can produce the target sequence. Reason about the problem however you wish and write out whatever working out you want. When you are finished please write a new line with `Updated production rules:`, and then write a new line for each of the updated production rules (including `rule_<n>:`), no need to rewrite the production rules which haven't changed. Do not write anything after the updated production rules.


"""
There are 19 terminals, ranging from 1 to 19.
Each terminal symbol occurs in the target sequence at least once.

There are 31 non-terminal symbols, ranging from A1 to A31.

Production rules:
rule_1: A1 -> A28 A23 A18 A15 A12 A2
rule_2: A2 -> 1
rule_3: A2 -> A6 A5 A4 A3
rule_4: A3 -> 3
rule_5: A4 -> 1
rule_6: A5 -> 1
rule_7: A5 -> A6
rule_8: A6 -> 1
rule_9: A6 -> A7 4
rule_10: A7 -> 1
rule_11: A7 -> A9 6
rule_12: A8 -> 1
rule_13: A9 -> 1
rule_14: A9 -> A10
rule_15: A9 -> A11 10
rule_16: A10 -> 1
rule_17: A11 -> 1
rule_18: A11 -> A7
rule_19: A11 -> A10
rule_20: A12 -> 1
rule_21: A12 -> A5 A8 A14 A13
rule_22: A13 -> 12 11
rule_23: A14 -> 1
rule_24: A15 -> 1
rule_25: A15 -> A8 A7 A17 A16
rule_26: A16 -> 14 13
rule_27: A17 -> 1
rule_28: A18 -> 1
rule_29: A18 -> A7 A11 A21 A19
rule_30: A19 -> A20 15
rule_31: A20 -> 4
rule_32: A21 -> 1
rule_33: A21 -> A22
rule_34: A22 -> 10
rule_35: A23 -> 1
rule_36: A23 -> A11 A10 A26 A24
rule_37: A24 -> 17 16
rule_38: A24 -> A25
rule_39: A25 -> 10
rule_40: A26 -> 1
rule_41: A26 -> A27
rule_42: A27 -> 9
rule_43: A28 -> 1
rule_44: A28 -> A10 A9 A31 A29
rule_45: A29 -> 19
rule_46: A29 -> A30
rule_47: A30 -> 9
rule_48: A31 -> 1
rule_49: A31 -> 5

Target sequence:
1 1 9 7 10 8 5 6 19 18 1 1 1 17 16 1 1 1 4 15 1 1 1 14 13 1 1 1 12 11 1 1 1 3 2
"""