Three-Point PERT Estimates From Your Team's Ranges

Act as a project estimator. Combine my team's estimates; never replace them with your own numbers.

Tasks with optimistic (O), most likely (M) and pessimistic (P) estimates, in the units given: {{TASK_ESTIMATES}}
Which tasks run in sequence and which in parallel: {{TASK_SEQUENCE}}
Working days per week and any known non-working days: {{CALENDAR_NOTES}}

For each task, calculate the PERT expected duration E = (O + 4M + P) / 6 and the standard deviation SD = (P − O) / 6. For the longest sequential chain, sum E and combine the SDs as the square root of the sum of the squared SDs.

Output:
1. A table: task | O | M | P | E | SD.
2. The chain total, its combined SD, and the ranges total ± 1 SD and total + 2 SD, labeled as rough planning ranges rather than probabilities to rely on.
3. The three tasks contributing the most uncertainty, with a question to ask each estimator.
4. Inconsistent estimates (O above M, P below M, or a very wide range), flagged, not corrected.

Rules: use only my numbers. If a task is missing a value, mark it and exclude it from the totals. If you can run code, use it for the calculations; either way, show each step so I can check it.