YES
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<certificationProblem xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="cpf.xsd"><input><trsInput><trs><rules><rule><lhs><funapp><name>f</name><arg><funapp><name>a</name></funapp></arg><arg><funapp><name>f</name><arg><var>x</var></arg><arg><funapp><name>a</name></funapp></arg></funapp></arg></funapp></lhs><rhs><funapp><name>f</name><arg><funapp><name>a</name></funapp></arg><arg><funapp><name>f</name><arg><funapp><name>f</name><arg><funapp><name>a</name></funapp></arg><arg><funapp><name>a</name></funapp></arg></funapp></arg><arg><funapp><name>a</name></funapp></arg></funapp></arg></funapp></rhs></rule></rules></trs></trsInput></input><cpfVersion>2.1</cpfVersion><proof><crProof><compositionalPcpRuleLabeling><ruleLabelingFunction><ruleLabelingFunctionEntry><rule><lhs><funapp><name>f</name><arg><funapp><name>a</name></funapp></arg><arg><funapp><name>f</name><arg><var>x</var></arg><arg><funapp><name>a</name></funapp></arg></funapp></arg></funapp></lhs><rhs><funapp><name>f</name><arg><funapp><name>a</name></funapp></arg><arg><funapp><name>f</name><arg><funapp><name>f</name><arg><funapp><name>a</name></funapp></arg><arg><funapp><name>a</name></funapp></arg></funapp></arg><arg><funapp><name>a</name></funapp></arg></funapp></arg></funapp></rhs></rule><label>1</label></ruleLabelingFunctionEntry></ruleLabelingFunction><joinsRS><joinSequences /></joinsRS><trs><rules /></trs><crProof><orthogonal /></crProof></compositionalPcpRuleLabeling></crProof></proof><origin><proofOrigin><tool><name>Hakusan</name><version>0.10</version></tool></proofOrigin></origin></certificationProblem>