{ if ($1==(alt "2")) { u[i]=u[i]"|"$2 alt=substr(alt,1,1) "2" } else { if (substr(alt,2,2)!=2) u[i]=u[i]"|" i=i+1 if (substr($1,1,1)!=substr(alt,1,1)) { u[i]=substr($1,1,1)"|||" i=i+1 } u[i]=$0 alt=$1 } } END { if (i%2==1) i2=(i-1)/2 else i2=i/2 j=i2 while (substr(u[j],1,1)==substr(u[i2],1,1)) j=j+1 k=0 while (k