Arthashastra
तद् विशिष्टं तु राजानम् आश्रितो दुर्गम् अविषह्यं वा चेष्टेत ॥
Hence, a weak king should either seek the protection of a powerful king or maintain himself in an impregnable fort.
english translation
tad viziSTaM tu rAjAnam Azrito durgam aviSahyaM vA ceSTeta ॥
hk transliteration by Sanscript