Arthashastra
परिक्षीणो वा अस्मै दुर्गं दत्त्वा निर्गच्छेत् ॥
Alternatively, once his means are depleted, he should hand over the fortress to him and depart.
english translation
parikSINo vA asmai durgaM dattvA nirgacchet ॥
hk transliteration by Sanscript