text: #!/usr/bin/env python
  
  import sys
  prevVals = [None, None, None]
  totalCoverage = 0
  nCoverage = 0
  for line in sys.stdin.readlines():
  	vals = line.split()
  	if (vals[0:3] != prevVals[0:3] and prevVals[0] is not None):
  		coverage = totalCoverage / nCoverage	
  		prevVals[-1] = coverage 
  		print "\t".join([str(i) for i in prevVals])
  		totalCoverage = 0
  		nCoverage = 0
  	totalCoverage += float(vals[-1])
  	nCoverage += 1.0
  	prevVals = vals
  