# Tally adjacent count fields of duplicate key names.

BEGIN {
   OFS = FS = "\t"
   key = ""
   sum = 0
   flg = 1
}

{
   if ( flg ) {
      flg = 0
      key = $1
   }
   if ( $1 == key ) {
      sum += $2
   } else {
      print key, sum
      key = $1
      sum = $2
   }
}

END {
   print key, sum
}