Image description: structure of nested programs
This image shows the program structure as follows.
Program-Id. A.
Program-Id. A1.
Program-Id. A11.
Program-Id. A111.
End Program A111.
End Program A11.
Program-Id. A12 is Common.
End Program A12.
End Program A1.
Program-Id. A2 is Common.
End Program A2.
Program-Id. A3 is Common.
End Program A13.
End Program A.
End of image description.