How to show Contracts of Account according to hierarchy on VF page?

Account is one object and Contract is another object.

I want to show Contracts of all Child Accounts on Ultimate Parent Account.

Below is the code for same.

**Controller**

public AccountHierarchyController(ApexPages.StandardController controller) {
        this.acc = (Account)controller.getRecord();
        this.accountList = new List<Account>();

        Account baseAccount = [SELECT Id, 
                               ParentId, 
                               Name,
                               Parent.Name,
                               (SELECT ContractNumber,SBQQ__ActiveContract__c,StartDate,Contract_renewed__c FROM Contracts),
                               (SELECT Id, Name FROM ChildAccounts)
                               FROM Account 
                               WHERE Id = :acc.id];
        accountList.add(baseAccount);

        // Traverse the hierarchy downwards
        Set<Id> accountsToQuery = new Map<Id, Account>(baseAccount.ChildAccounts).keySet();
        while (accountsToQuery.size() > 0) {
            List<Account> thisLevelAccounts = [SELECT Id, Name, Parent.Name,
                                               (SELECT ContractNumber,SBQQ__ActiveContract__c,StartDate,Contract_renewed__c FROM Contracts),
                                               (SELECT Id, Name FROM ChildAccounts)
                                               FROM Account
                                               WHERE Id IN :accountsToQuery];
            accountsToQuery = new Set<Id>();

            for (Account a : thisLevelAccounts) {
                // Add this Account (with its Contracts) to the list.
                accountList.add(a);

                // Add this Account's children to the query for the next level.
                for (Account child : a.ChildAccounts) {
                    accountsToQuery.add(child.Id);
                }
            }
        }
    }
    }

**Vf Page**

    <apex:page title="Contract" standardController="Account" extensions="AccountHierarchyController">
    <apex:outputPanel id="cont">
        <apex:pageBlock title="Contracts">
            <apex:repeat value="{! accountList }" var="a">
                <apex:pageBlockSection title="{! a.Name + IF(NOT(ISBLANK(a.ParentId)), ' (child of ' + a.Parent.Name + ')', '') }">
                    <apex:pageBlockTable value="{! a.Contracts }" var="con" id="conlist" title="Contract">
                        <apex:column value="{!con.ContractNumber}"/>
                        <apex:column value="{!con.SBQQ__ActiveContract__c}" />
                        <apex:column value="{!con.StartDate}" />
			<apex:column value="{!con.Contract_renewed__c}" />
                    </apex:pageBlockTable>
                </apex:pageBlockSection>
            </apex:repeat>
        </apex:pageBlock>
    </apex:outputPanel>
</apex:page>

But when I am trying to save it's showing:

Compile error:Unexpected token 'AccountHierarchyController'.

Can someone can help me on this.