In an enterprise, no two employees have jobs of the same difficulty and no two of them take the same salary. Every employee gave the following two claims:
(i) Less than $12$ employees have a more difficult work;
(ii) At least $30$ employees take a higher salary.
Assuming that an employee either always lies or always tells the truth, find how many employees are there in the enterprise.
1. Let there be \( n \) people in the enterprise. Each employee makes two claims:
   - (i) Less than 12 employees have a more difficult job.
   - (ii) At least 30 employees take a higher salary.

2. We need to determine the number of employees \( n \) such that the conditions hold true for either all truth-tellers or all liars.

3. **Claim:** In the top 30 people for salary, they are all liars.
   - **Proof:** Assume that there is a truth-teller in that group. Then they say "at least 30 people have a higher salary than me," which implies that there are 30 people above them in salary. This is a contradiction because we assumed that this is at most 29. Therefore, the claim is proven.

4. Consequently, the bottom \( n-30 \) people for salary are all truth-tellers because they truthfully say that at least 30 people have a higher salary.

5. Since the top 30 people in salary all lie about (i), we must have that there are at least 12 people above the employee that works the most difficult job in the top 30 salary. This means that there are at least 12 people outside of the top 30 salary, so there are at least \( 30 + 12 = 42 \) people in total.

6. Since the bottom \( n-30 \) people all tell the truth about (i), the lowest difficulty worker in that group must have at most 11 people above them, so there are at most 12 people in this group. Thus, there are at most \( 30 + 12 = 42 \) people in total.

7. Therefore, \( 42 \ge n \ge 42 \), which implies \( n = 42 \).

8. **Construction:**
   - Consider the following leaderboard for salary and difficulty:
     - Salary (highest to lowest): \( E_{42}, E_{41}, E_{40}, \dots, E_1 \).
     - Difficulty (highest to lowest): \( E_1, E_2, E_3, \dots, E_{41}, E_{42} \).
   - \( E_i \) is a truth-teller for \( i = 1, 2, \dots, 12 \), and a liar for \( i = 13, 14, 15, \dots, 42 \).

9. Verification:
   - For \( i = 1, 2, \dots, 12 \):
     - \( E_i \) tells the truth about (i) because only \( i-1 < 12 \) people work a more difficult job.
     - They tell the truth about (ii) because \( 42-i \ge 30 \) people have a higher salary.
   - For \( i = 13, 14, \dots, 42 \):
     - \( E_i \) lies about (i) because there are \( i-1 \ge 12 \) people that work a more difficult job.
     - They lie about (ii) because there are \( 42-i < 30 \) people that have a higher salary.

The final answer is \( \boxed{42} \).