import arcpy
country = arcpy.GetParameter(0)
query = '"CNTRY_NAME" = ' + str(country)
popRankings = []
search = arcpy.da.SearchCursor('cities', ["CNTRY_NAME", "POP_RANK"], query)
for rank in search :
    popRankings.append(rank[1])
popRankings.sort()
if len(popRankings) % 2 == 0 :
    median1 = popRankings[len(popRankings)//2]
    median2 = popRankings[len(popRankings)//2]
    median = (median1 + median2)/2
    arcpy.AddMessage("The median population rank for " + country + " is " + median + ".")
else :
    median = popRankings[len(popRankings)//2]
    arcpy.AddMessage("The median population rank for " + country + " is " + median + ".")