0(1) element: null
1(2) element: PyTryExceptStatement
2(3,9) element: PyTryPart
3(4,9) element: PyAssignmentStatement
4(5,9) READ ACCESS: int
5(6,9) element: PySubscriptionExpression
6(7,9) READ ACCESS: sys
7(8,9) element: PyCallExpression: int
8(9,15) WRITE ACCESS: n
9(10) element: PyExceptPart
10(11) READ ACCESS: ValueError
11(12) element: PyPrintStatement
12(13) element: PyExpressionStatement
13(14) READ ACCESS: exit
14(15) element: PyCallExpression: exit
15(16) element: PyPrintStatement
16(17) READ ACCESS: str
17(18) READ ACCESS: n
18(19) element: PyCallExpression: str
19() element: null