read K
read line
SCORE_RANGE=($line)

RANGE=$((1*${SCORE_RANGE[1]}-${SCORE_RANGE[0]}))

if [ ${K} -eq 0 ]; then
 echo 'NG'
 exit
fi

if [ $(( ${SCORE_RANGE[0]} % ${K} - 1 )) -eq 0 ]; then
echo 'OK'
exit 
fi

if [ ${RANGE} -gt ${K} ] ; then
  echo 'OK'
else
  echo 'NG'
fi
