#!/usr/bin/awk -f
BEGIN {
   FS=","
   x=y=nil
   dup=1
}

($2==x && $3==y){
   if(dup) {
      printf "%s\n%s\n",last,$0;
   } else {
      print $0
   };
   dup=0
}

($2!=x || $3!=y) {dup=1}
{x=$2; y=$3; last=$0}