Shell Programming and Scripting

input file 
/tmp/tmp.txt

1226037463l
1226037422ll


while read -r LINE
do
        if [ $start=0 ];
        then
        FRIST=`echo $LINE | awk -F"|" 'NR==1''{print $1}'`
        echo $FRIST
        SECOND=`echo $LINE | awk -F"|" 'NR==2''{print $1}'`
        echo $SECOND
done < /tmp/temp.txt

But the output is only 
1226037463l

while read -r LINE
do
if [ $start=0 ];
then
FRIST=`echo $LINE | awk -F"|" 'NR==1''{print $1}'`
echo $FRIST
SECOND=`echo $LINE | awk -F"|" 'NR==2''{print $1}'`
echo $SECOND
fi
done < /tmp/temp.txt

FRIST=`echo | awk 'NR==1 {print;exit}' /tmp/temp.txt`
echo $FRIST
SECOND=`echo | awk 'NR==2 {print;exit}' /tmp/temp.txt`
echo $SECOND

FIRST=`awk 'BEGIN{FS="|";OFS=" "}NR==1{print $1}' /temp/temp.txt`
SECOND=`awk 'BEGIN{FS="|";OFS=" "}NR==2{print $1}' /temp/temp.txt`

FRIST VALUE IS 1226045443l
SECOND VALUE IS 1226045402l

Error Im getting 

expr: non-numeric argument


my code 

str= `expr $FRIST + $SECOND`
echo $str

I tried below also

str= `expr $FRIST + $SECOND | bc -l`
echo $str

#! /bin/bash

FIRST=`awk 'BEGIN{FS="|";OFS=" "}NR==1{print $1}' /temp/temp.txt` 
# NOT     FIRST=1226045443l     BUT    FIRST=1226045443
SECOND=`awk 'BEGIN{FS="|";OFS=" "}NR==2{print $1}' /temp/temp.txt`
# NOT     SECOND=1226045402l     BUT     SECOND=1226045402

((str=$FIRST+$SECOND))  #or str=$((FIRST+SECOND))
echo $str

#! /bin/bash

FIRST=`awk 'BEGIN{FS="|";OFS=" "}NR==1{print $1}' /temp/temp.txt`
SECOND=`awk 'BEGIN{FS="|";OFS=" "}NR==2{print $1}' /temp/temp.txt`

let str=$FIRST+$SECOND
echo $str