Is there a set size that message box can be. My message box is cutting off the last three lines and show's the OK button. See below...

=MESSAGEBOX("THIS IS A test COMPUTER SYSTEM. BEFORE PROCESSING CLASSIFIED INFORMATION, CHECK THE SECURITY ACCREDITATION LEVEL OF THIS "+CHR(13) ;
+ "CONSENT TO MONITORING. UNAUTHORIZED USE OF THIS DOD COMPUTER SYSTEM MAY SUBJECT YOU TO CRIMINAL PROSECUTION. EVIDENCE OF "+CHR(13) ;
+ "UNAUTHORIZED USE COLLECTED DURING MONITORING MAY BE USED FOR ADMINISTRATIVE, CRIMINAL, OR OTHER ADVERSE ACTION. USE OF "+ CHR(13) ;
+ "THIS SYSTEM CONSTITUTES CONSENT TO MONITORING FOR ALL LAWFUL PURPOSES.",0+48, ;