南城以念北城人北城以念南城人
[nán chéng yĭ niàn bĕi chéng rén bĕi chéng yĭ niàn nán chéng rén]
Literally 'The south city remembers the people in the north city; the north city remembers the people in the south city'. This evokes a sentiment of mutual longing and nostalgia between people living in different places, often with romantic overtones.