volodya like listen heavy metal occasionally read no wonder volodya especially interested text concern favourite music styleVolodya call stre powerful start heavy end metal find powerful substring substre Volodya mean subsequence consecutive character string give text make hero especially joyful recently feel enormous fit energy read certain text So Volodya decide count powerful substring text brag day long help difficult task two substring consider different appear different position textfor simplicity let assume Volodyas text represent single string