Valmiki Ramayana Sundara Kanda Sarga 13 Shloka 26
Original Shlokaविनष्टौ भ्रातरौ श्रुत्वा भरतोऽपि मरिष्यति।।5.13.26।। भरतं च मृतं दृष्ट्वा शत्रुघ्नो न भविष्यति।
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भ्रातरौ both brothers, विनष्टौ dead, श्रुत्वा after hearing, भरतोऽपि Bharata also, मरिष्यति will die, मृतम् dead, भरतम् of Bharata, दृष्ट्वा on seeing, शत्रुघ्नश्च even Satrughna, न भविष्यति will not live.
"On hearing the death of both the brothers Bharata will also die. On seeing this Satrughna will also not live.