===== ISTEM =====
Solve the following programming task.

TASK: Longest Common Subsequence

Write a function 'longest_common_subsequence(text1, text2)' that computes the length of the longest common subsequence (LCS) of the two given strings.

STARTER CODE (python):
def longest_common_subsequence(text1: str, text2: str) -> int:
    # Write your code here
    pass


RULES:
- Keep the function name and signature EXACTLY as given.
- Return working code only. No explanations.
- Put the code in a single ``` block.
- Try to solve it first. If you genuinely cannot, write only this single
  line instead of producing faulty code: CANNOT_SOLVE

===== HAM YANIT =====
```python
def longest_common_subsequence(text1: str, text2: str) -> int:
    m = len(text1)
    n = len(text2)
    
    dp = [[0] * (n + 1) for _ in range(m + 1)]
    
    for i in range(1, m + 1):
        for j in range(1, n + 1):
            if text1[i - 1] == text2[j - 1]:
                dp[i][j] = dp[i - 1][j - 1] + 1
            else:
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])
    
    return dp[m][n]
```