SNMP OID, get only the first value

Hi,

I need help to get just the first value of this OID "enclTempSensorsCurrentTemp 1.3.6.1.4.1.789.1.21.1.2.1.25", it gives as result a string like this: 18C (64F) ambient, 26C (78F), 26C (78F),  in my case I just want to get the first value"18" in order to create a custom MP that will collect and monitor the temperature of the device.

I'll appreciate any suggestion.