Thanks I got it now.I have one question though , in the documentation of append it is given that <table class="boxed" cellspacing="0"><tbody><tr><td>(<a name="(dep._((quote._~23~25kernel)._append))"></a><a name="(def._((quote._~23~25kernel)._append))"></a><a href="file:///usr/local/plt/doc/reference/pairs.html#%28def._%28%28quote._%7E23%7E25kernel%29._append%29%29" class="schemevaluelink">append</a> lst ...) $B"*(B <a href="file:///usr/local/plt/doc/reference/pairs.html#%28def._%28%28quote._%7E23%7E25kernel%29._list%7E3f%29%29" class="schemevaluelink">list?</a></td> </tr><tr><td>  lst : <a href="file:///usr/local/plt/doc/reference/pairs.html#%28def._%28%28quote._%7E23%7E25kernel%29._list%7E3f%29%29" class="schemevaluelink">list?</a></td> </tr><tr><td>(<a href="file:///usr/local/plt/doc/reference/pairs.html#%28def._%28%28quote._%7E23%7E25kernel%29._append%29%29" class="schemevaluelink">append</a> lst ... v) $B"*(B <a href="file:///usr/local/plt/doc/reference/Data-structure_Contracts.html#%28def._%28%28lib._scheme/private/contract-guts..ss%29._any/c%29%29" class="schemevaluelink">any/c</a></td> </tr><tr><td>  lst : <a href="file:///usr/local/plt/doc/reference/pairs.html#%28def._%28%28quote._%7E23%7E25kernel%29._list%7E3f%29%29" class="schemevaluelink">list?</a></td> </tr><tr><td>  v : <a href="file:///usr/local/plt/doc/reference/Data-structure_Contracts.html#%28def._%28%28lib._scheme/private/contract-guts..ss%29._any/c%29%29" class="schemevaluelink">any/c</a></td> </tr></tbody></table>When given all list arguments, the result is a lists that contains all of the elements of the given lists in order. The last argument is used directly in the tail of the result.The last argument need not be a list, in which case the result is an “improper list. Can someone please explain what does an improper list means? Aditya