All three women were convicted in August of hooliganism motivated by religious hatred for an irreverent protest against President Vladimir Putin.
They argued in court on Wednesday that their impromptu performance inside Moscow's main cathedral in February was political in nature and not an attack on religion.
The judge ruled that Yekaterina Samutsevich's sentence should be suspended because she was thrown out of the cathedral by guards before she could take part in the performance.
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