Nested If in DataStage Transformer

I am using below nested if condition in transformer. How ever it is giving error. Can some one assist me to resolve the error:

IF IsNotNull(lnkReadHabsClob.NUM_57_A) THEN ( IF LEN57A < 2 THEN Trim(lnkReadHabsClob.BENEFICIARY_FI_SKEY_57A) ELSE IF LEN57A > 2 THEN Trim(lnkReadHabsClob.BENEFICIARY_FI_SKEY_57A[LEN57A,11] ) ) ELSE ( IF IsNotNull(lnkReadHabsClob.NUM_58_A) AND LEN58A < 2 THEN TRIM(lnkReadHabsClob.BENEFICIARY_FI_SKEY_58A) ELSE IF IsNotNull(lnkReadHabsClob.NUM_58_A) AND LEN58A > 2 THEN TRIM(lnkReadHabsClob.BENEFICIARY_FI_SKEY_58A[LEN58A,11]) ) ELSE lnkReadHabsClob.BENEFICIARY_FI_SKEY_58A)