Another symbol volume

pull another symbol volume
dafult:BF(blue)/MEX(red)/FINEX(lime)
*need MEX's volume devided XBTUSD
if you input another symbol as sym2, please comment out line 11 and remove "/mext" on line 12

mext=security(sym2,period,close)
plot(sym2v/mext,color=red)

//mext=security(sym2,period,close)
plot(sym2v,color=red)