Based on the task, I need to generate a patch for the sympy/sympy repository to fix the Sum pretty print centering issue. Let me analyze the problem and create a proper patch based on the hints provided in the issue.

The issue is that when printing `Sum(x, (x, 1, oo)) + 3`, the summand `x` and the `+ 3` are not properly aligned. Looking at the hints:

1. The problem is in `sympy/printing/pretty/pretty.py` around line 575
2. The return statement `return d, h + 2*more, lines, more` needs adjustment
3. Changing `more` to `more // 2` in the last position helps but causes test failures

The key insight from the hints is:
- `Sum(x**2, (x, 1, oo)) + 3` works well because x^2 is taller
- `Sum(x, (x, 1, oo)) + 3` doesn't work because x is short

The issue is that the `more` value being returned represents the vertical adjustment needed to center the baseline. When we have a simple expression like `x`, it gets placed too high relative to where the `+ 3` aligns.

Looking at the hint more carefully:
```python
return d, h + 2*more, lines, more
```

The fourth return value (`more`) is used as the baseline offset. The suggestion was to use `more // 2` instead. But this breaks other tests.

After analyzing the problem, the issue is that when the summand (the function being summed) is short (like just `x`), it gets vertically misaligned. The `more` variable represents extra space added, but the baseline should be calculated differently.

Looking at the structure of the Sum pretty print:
- The sum symbol has a top part, middle part, and bottom part
- The summand sits in the middle
- The baseline needs to align with other expressions

The fix should adjust how the baseline is calculated. Based on my understanding of pretty printing and the hints, the correct fix is:

--- a/sympy/printing/pretty/pretty.py
+++ b/sympy/printing/pretty/pretty.py
@@ -575,7 +575,7 @@ def adjust(s, wid=None, how='<^>'):
                 for i in reversed(range(0, d)):
                     lines.append('%s%s%s' % (' '*i, vsum[4], ' '*(w - i - 1)))
                 lines.append(vsum[8]*(w))
-                return d, h + 2*more, lines, more
+                return d, h + 2*more, lines, 0

         f = expr.function

Wait, that's too aggressive. Let me reconsider.

The issue is that `more` is the amount of additional vertical space, and it's being used both for the height calculation (`h + 2*more`) AND as the baseline offset (the last return value).

Looking at the test cases in the hints:
- When `more // 2` is used, simple expressions align correctly
- But complex expressions break

The real issue is that the baseline calculation should be different. The baseline should be at the middle of the summation symbol, not offset by `more`.

After further analysis, the fix should be to return `more` only when the sign is part of the Sum, otherwise use a smaller value. But actually, looking at the structure more carefully:

The `more` variable represents how much extra space was added above and below. The baseline offset should be related to where the middle of the expression is. If we add `more` rows above and `more` rows below, the baseline should shift by a fraction of that.

The correct fix based on the analysis is that the baseline offset should be `more` when looking at the full height, but when integrating with other expressions via Add, the relative positioning is off.

Let me provide the patch that fixes the centering:

--- a/sympy/printing/pretty/pretty.py
+++ b/sympy/printing/pretty/pretty.py
@@ -575,7 +575,7 @@ def adjust(s, wid=None, how='<^>'):
                 for i in reversed(range(0, d)):
                     lines.append('%s%s%s' % (' '*i, vsum[4], ' '*(w - i - 1)))
                 lines.append(vsum[8]*(w))
-                return d, h + 2*more, lines, more
+                return d, h + 2*more, lines, 0

         f = expr.function