awk ' BEGIN {
a='$1'
bl="     "
nid = 0
}
{
if(NR == 1) {
  prec=$0
  champ1=$1 
  champ2=$2 
  champ3=$3 
  champ4=$4 
  getline }
if(champ3 >= $3-a && champ3 <= $3+a && champ4 >= $4-a && champ4 <= $4+a) {
if(champ1 < $2)
  printf" %4d %4d\n",champ1,$1
else
  printf" %4d %4d\n",$1,champ1
  nid++
getline }
prec=$0
champ1=$1
champ2=$2
champ3=$3
champ4=$4
}
END {
printf" Nombre de cas rencontres: %3d\n\n",nid
} '