Valmiki Ramayana Ayodhya Kanda Sarga 8 Shloka 19
Original Shlokaराज्यं यदि हि रामस्य भरतस्यापि तत्तदा। मन्यते हि यथात्मानं तथा भ्रातृ़ंश्च राघवः।।2.8.19।।
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रामस्य Rama's, राज्यं यदि if it is his kingdom, तत् that one, तदा then, भरतस्यापि Bharata's also, राघव: Rama, आत्मानम् own self, यथा as, भ्रातृ़ंश्च his brothers also, तथा in that way, मन्यते considers.
If the kingdom is Rama's, it is also Bharata's, since Rama regards his brothers as his own self