20 day momentum

//version=3
strategy("Momentum Strategy", overlay=true)
length = input(12)
price = close

momentum(seria, length) =>
mom = seria - seria[length]
mom

mom0 = momentum(price, length)
mom1 = momentum( mom0, 20)

if (mom0 > 0 and mom1 > 0)
strategy.entry("MomLE", strategy.long, stop=high+syminfo.mintick, comment="MomLE")
else
strategy.cancel("MomLE")

if (mom0 < 0 and mom1 < 0)
strategy.entry("MomSE", strategy.short, stop=low-syminfo.mintick, comment="MomSE")
else
strategy.cancel("MomSE")

//plot(strategy.equity, title="equity", color=red, linewidth=2, style=areabr)