I can plot two using this

proc gplot data=outdata;
plot meanmaxcpu*hour/ haxis=0 to 23 by 1 vaxis=0 to 100 by 10;
plot2 ubmaxcpu*hour/ haxis=0 to 23 by 1 vaxis=0 to 100 by 10;;
symbol1 color=green interpol=spline width=2 value=dot h=1;
symbol2 color=blue interpol=spline width=2 value=dot h=1;
axis1 label=hour order=0 to 23 by 1;
axis2 label=CPU;
haxis=axis1 hminor=0
vaxis=axis2 vminor=1
caxis=red;
title 'Plot of Hour versus Max. CPU';
run;
proc print; run;


but when I plot the third it doesn't work (plot3 turns to red font)


proc gplot data=outdata;
plot meanmaxcpu*hour/ haxis=0 to 23 by 1 vaxis=0 to 100 by 10;
plot2 ubmaxcpu*hour/ haxis=0 to 23 by 1 vaxis=0 to 100 by 10;
plot3 lbmaxcpu*hour/ haxis=0 to 23 by 1 vaxis=0 to 100 by 10;
symbol1 color=green interpol=spline width=2 value=dot h=1;
symbol2 color=blue interpol=spline width=2 value=dot h=1;
axis1 label=hour order=0 to 23 by 1;
axis2 label=CPU;
haxis=axis1 hminor=0
vaxis=axis2 vminor=1
caxis=red;
title 'Plot of Hour versus Max. CPU';
run;
proc print; run;