set key graph 0.4,0.95
set label "4C" at graph 0.02,0.95
set xlabel "objective functions"
set ylabel "time (seconds)
set terminal fig big thickness 1 fontsize 18
set pointsize 1
plot "trial4C.plt" index 0 t "version-4" with linespoints pointtype 5
replot "trial4C.plt" index 1 t "version-5" with linespoints pointtype 1
set output "trial4C.fig"
replot