from my code i want to check which is greater

Question

  Declare @strAlphaNumeric varchar (50) = 'ARPA/B147 ' 

Declare @strAlphaNumeric1 varchar (50) = 'ARPA/B146 ' 

DECLARE @intAlpha INT

SET @intAlpha = PATINDEX('%[0-9]%', @strAlphaNumeric)

SET @intAlpha = PATINDEX('%[0-9]%', @strAlphaNumeric1)

select Cast(SUBSTRING(@strAlphaNumeric,@intAlpha, len(@strAlphaNumeric)) as int)

select Cast(SUBSTRING(@strAlphaNumeric1,@intAlpha, len(@strAlphaNumeric1)) as int)

select SUBSTRING(@strAlphaNumeric,1,@intAlpha-1)

select SUBSTRING(@strAlphaNumeric1,1,@intAlpha-1)

Running the above code shows output as follows

147

146

ARPA/B

ARPA/B

I want to check 147 or 146 which is greater.

From the above 147  is greater.

for getting a output 147.

from my above code what changes i have to made to get 147 output.