#!/usr/bin/env python

import sys,os

startcol=0
if "-s" in sys.argv:
    startcol=int(sys.argv[sys.argv.index("-s")+1])

lines=sys.stdin.readlines()

for l in lines:
    tok=l.split()
    l=l.strip()
    

    avg=0;
    cnt=0;
    for i in tok[startcol:]:
        cnt+=1
        avg+=float(i)
        
        
    if cnt!=0:
        print l,avg/cnt
    else:
        print l,'NAN'