19+19+19+19+19+19+19+20
=(20-1)+(20-1)+(20-1)+(20-1)+(20-1)+(20-1)+(20-1)+20
=20-1+20-1+20-1+20-1+20-1+20-1+20-1+20
=20×8-1×7
=160-7
=153
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