You want to create a program that assigns a letter grade based on a given numerical score. The goal is to:
1. Take an input value representing the score.
2. Compare the score to specific grade boundaries (e.g., 80, 70, 60, etc.).
3. Assign the corresponding letter grade based on the highest boundary the score meets or exceeds.
4. If the score does not meet any boundary, assign a default grade.
The solution should demonstrate the use of the `zip` function to pair letter grades with their corresponding score thresholds.
### Solution
1. **Input Score:**
- The user inputs a score, which is stored in the variable `m`. This score will determine the corresponding letter grade.
2. **Pair Grades and Score Thresholds:**
- Using `zip`, you pair each letter grade (A, B, C, D) with a corresponding score threshold (80, 70, 60, 50). The `zip` function creates an iterator that produces tuples like `('A', 80)`, `('B', 70)`, etc.
3. **Iterate and Compare:**
- A `for` loop iterates over each pair of grade and score threshold. For each pair:
- If the input score `m` is greater than or equal to the current score threshold, the corresponding letter grade is stored in the variable `g`, and the loop is exited using `break`. This ensures the highest grade threshold that is met or exceeded is selected.
4. **Handle Low Scores:**
- If none of the thresholds are met (i.e., the input score is below 50), the `else` block executes, assigning the letter grade 'U' (representing "ungraded" or a failing grade). The `else` block runs only if the `for` loop completes without encountering a `break`.
5. **Output the Grade:**
- Finally, the letter grade stored in `g` is printed.
### Key Concept (Using `zip`):
The `zip` function pairs up the letter grades with their corresponding score thresholds, allowing you to iterate over them together. This demonstrates how `zip` can be used to link related data (in this case, letter grades and score thresholds) and process them simultaneously.
