set terminal png color small
set size 0.7,1
set xlabel "log file number"
set ylabel "stamps"
set key below
set grid xtics ytics
plot 'karen_s.dat' with line,'kaho_s.dat' with line, 'mamoru_s.dat' with line,'sakuya_s.dat' with line,'hinako_s.dat' with line,'marie_s.dat' with line,'shirayuki_s.dat' with line,'rinrin_s.dat' with line,'chikage_s.dat' with line,'haruka_s.dat' with line, 'yotsuba_s.dat' with line, 'aria_s.dat' with line