Background: Population has outstripped the supply of freshwater, usually from rainfall. The northern atolls get 50 inches (1,300 mm) of rainfall annually; the southern atolls about twice that. The threat of drought is commonplace throughout the island chains.
Question: How many millimeters of rain do the northern atolls of the Marshall Islands receive?
Answer:<extra_id_0>.
<extra_id_0> 1,300<extra_id_1>