In standard procedural programming and algorithm design, a variable must be declared before it can be assigned a value or evaluated, and outputting data is generally the final step of a calculation sequence. The provided sequence attempts to output an undeclared, uncalculated variable in step 1 and declares it at the very end in step 4. By swapping step 1 and step 4, the algorithm establishes the correct logical sequence: it first declares the variable (new step 1), calculates the initial arithmetic difference (step 2), applies the conditional logic to ensure the value is positive (step 3), and finally outputs the resolved variable (new step 4).

Option A: Switching steps 1 and 2 places the assignment before the declaration and still executes the output command before the conditional check can guarantee a positive integer.

Option B: Switching steps 2 and 4 places the variable declaration second, leaving the initial output step executing first, which will fail as the variable is neither declared nor calculated.

Option D: Switching steps 3 and 4 leaves the output step at the beginning, meaning the algorithm will attempt to print an uninitialized variable before any calculations occur.

MIT OpenCourseWare (Massachusetts Institute of Technology): 6.0001 Introduction to Computer Science and Programming in Python. Lecture 1: "What is Computation?" Section on declarative knowledge, variables, and procedural sequencing. This courseware establishes the fundamental requirement that variables must be declared and initialized prior to evaluation or output.

Dijkstra, E. W. (1970): Notes on Structured Programming. (EWD249). Section 3: "On the Reliability of Mechanisms." Discusses strict sequential execution and the necessity of state initialization (variable declaration) preceding state mutation and output in algorithmic design.