Let the first six terms of Kitty\textquotesingle s sequence be $$a$$, $$b$$, $$c$$, $$18$$ and $$29$$ respectively.  Then $$c+ 18= 29$$, so $$c= 11$$. Hence $$b+11= 18$$, so $$b=7$$.  Therefore, $$a+7=11$$, so $$a=4$$. 
Kitty writes down a sequence of five integers. The rule she uses is, "after the first two terms, each term is the sum of the two previous terms." She sequence is~\uline{~~~~~~~~~~}~,~\uline{~~~~~~~~~~}~,~\uline{~~~~~~~~~~}~, $$18$$, $$29$$.  What is her first term? ． 
Options:
1. $$0 $$ 
2. $$ 3 $$ 
3. $$ 4 $$ 
4. $$ 5 $$ 
5. $$ 7$$ 