[INSTRUCTIONS]

You are a program-analysis assistant. Your task is to statically analyze the control dependence of a given code snippet. 

## 1. Control Dependence Definition
  Control dependence captures the influence of control-flow decisions on the execution of statements.

  A statement `S2` is control-dependent on `S1` if there is a **transitive** (indirect) chain of **direct** control dependencies from `S1` to `S2`. This is equivalent to saying that `S1` has control dependence over `S2`, meaning `S1`’s condition influences whether `S2` executes.


  **Direct Control Dependence**:
  A statement `S2` is **directly** control-dependent on a statement `S1` if:
  
  1.	`S1` is a conditional control statement (e.g., an `if`, `while`, `for`, `switch`, etc.).
  
  2.	`S1` directly determines whether `S2` executes. That is, `S1` has multiple successor branches, 

  - there exists **at least one branch** in which `S2` **always executes**, and
  - there exists **at least one other branch** in which `S2` does **not necessarily execute**.

    “Not necessarily execute” means that `S2` might execute or might not, but it is **not guaranteed** to execute in that branch.

  `S2` is **control-dependent** on `S1` if there exists a **transitive chain** of control dependencies from `S1` to `S2`, where each intermediate step in the chain represents a **direct** control dependence between two statements.



## 2. Output Format
When asked, "Which lines have control dependence over `targetLine`? List all such lines." You should respond in JSON format as follows:
```json
{
  "ControlDependenceSources": [S1, ..., S2]
}
```
  
If you believe there is no line that has control dependence over `targetLine`, respond:
```json
{
  "ControlDependenceSources": []
}
```


    

## 3. Interprocedural Control Dependence
  All dependence analysis is performed within **a single function**. We do not track dependencies across function boundaries. The analysis only applies to variables and control structures inside the **specified function**.


## 4. Example Code Snippet

### Example 1

```python
1  if x > 0:
2      y = 10       # this line is directly control-dependent on line 1 (x>0)
3      if y > 5:
4          z = 20   # this line is directly control-dependent on line 3 (y>5)
5          w = 30   # this line is directly control-dependent on line 3 (y>5)
6  v = 40           # this line is NOT control-dependent on any line
```


**Analysis**:
- Line 2 is directly control-dependent on line 1 (`x>0`)
- Lines 4 and 5 are directly control-dependent on line 3 (`y>5`).
- Lines 4 and 5 are **indirectly** control-dependent on line 1 (`x>0`) becasue even if line 1 (`x>0`) is `true`, lines 4 and 5 may not execute if line 3’s condition (`y>5`) is `false`. However, since control dependence is transitive, lines 4 and 5 are **indirectly** control-dependent on line 1. 
- Line 6 is not control-dependent on any lines because Line 6 always executes, regardless of whether line 1 (`x>0`) or line 3 (`y>5`) is true or false.



#### Example Question 1.1: 
Which lines have control dependence over line `5`? List all such lines.


**Output**: 
```json
{
  "ControlDependenceSources": [1, 3]
}
```

#### Example Question 1.2:
Which lines have control dependence over line `6`? List all such lines.

**Output**: 
```json
{
  "ControlDependenceSources": []
}
```


### Example 2

```python
1  count = 0
2  if count < 5:
3      count += 1
4  print("Step 1 done")
5  while count < 10:
6      if count == 7:
7          break
8      if count % 2 == 0:
9          continue
10     count += 2
11     if count > 9:
12         count = 9
13     print("Iteration done")
14 print("End of program")
```

#### Example Question 2.1: 
Which lines have control dependence over line `13`? List all such lines.

**Analysis**:
  - Line 13 is directly control-dependent on line 8 because if line 8 evaluates to `true`, continue skips line 13 for that iteration.
  - Line 8 is directly control-dependent on line 6 because if line 6 evaluates to `true`, the break statement terminates the loop, preventing line 8 from executing.
  - Line 6 is directly control-dependent on line 5 because the loop condition at line 5 determines whether line 6 executes. If line 5 evaluates to `false`, execution skips the loop entirely.


**Output**:
```json
{
  "ControlDependenceSources": [5, 6, 8]
}
```

#### Example Question 2.2: 
Which lines have control dependence over line `10`? List all such lines.


**Analysis**: Similar to the explanation above, line 8 is an `if` condition inside the `while` loop with a `continue`, so it can make the execution skip the rest of the loop entirely, including line 10. 



**Output**:
```json
{
  "ControlDependenceSources": [5, 6, 8]
}
```


#### Example Question 2.3: 
Which lines have control dependence over line `14`? List all such lines.

**Analysis**: Line 14 is outside the while loop (lines 5 -- 13) and will be executed regardless of the condition. 

**Output**:
```json
{
  "ControlDependenceSources": []
}
```


#### Example Question 2.4: 
Which lines have control dependence over line `12`? List all such lines.

**Analysis**: Line 2 doesn't affect whether line 12 is reached. The condition in line 2 only controls whether line 3 is executed. Line 12 is in while loop (line 5 -- 13) and will or will not be executed regardless of the condition in line 2. 

**Output**:
```json
{
  "ControlDependenceSources": [5, 6, 8, 11]
}
```

---

[YOUR TURN]

Below is **your target snippet**. 

```Python
1   import sys
2   sys.setrecursionlimit(10 ** 6)
3   INF = float("inf")
4   MOD = 10 ** 9 + 7
5   def input():
6       return sys.stdin.readline().strip()
7   def main():
8       H, W = map(int, input().split())
9       A = []
10      cnt = 0
11      for _ in range(H):
12          a = list(map(int, input().split()))
13          cnt += sum(a)
14          A.append(a)
15      ans = []
16      for h in range(H):
17          if h % 2 == 0:
18              for w in range(W):
19                  if h == H - 1 and w == W - 1:
20                      continue
21                  if A[h][w] % 2 == 1:
22                      if w == W - 1:
23                          A[h][w] -= 1
24                          A[h + 1][w] += 1
25                          ans.append((h, w, h + 1, w))
26                      else:
27                          A[h][w] -= 1
28                          A[h][w + 1] += 1
29                          ans.append((h, w, h, w + 1))
30                  else:
31                      continue
32          else:
33              for w in range(W)[::-1]:
34                  if h == H - 1 and w == 0:
35                      continue
36                  if A[h][w] % 2 == 1:
37                      if w == 0:
38                          A[h][w] -= 1
39                          A[h + 1][w] += 1
40                          ans.append((h, w, h + 1, w))
41                      else:
42                          A[h][w] -= 1
43                          A[h][w - 1] += 1
44                          ans.append((h, w, h, w - 1))
45                  else:
46                      continue
47      print(len(ans))
48      for a, b, c, d in ans:
49          print(a + 1, b + 1, c + 1, d + 1)
50  if __name__ == "__main__":
51      main()
```


**Question**: Which lines have control dependence over line `28` in function `main`? List all such lines.

**Output**:


Ground truth answer: yes