pro difference,dt121,dt122,dt123,dt124,dt1240

    min=24.*60
    dd10=(dt121-dt1240)*min
    dd20=(dt122-dt1240)*min
    dd30=(dt123-dt1240)*min
    dd40=(dt124-dt1240)*min
    psout,012,'difference.ps'
    plot,dd10,xrange=[0,14],xsty=1,ytitle='Difference between others and Roger in minites'
    oplot,dd20,color=2
    oplot,dd30,color=3
    oplot,dd40,color=4
    oplot,[0,14],[0,0],color=4,line=3
    psdone
    print,'difference.ps'

end