===== 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, n = len(text1), len(text2)
    dp = [[0] * (n + 1) for _ in range(m + 1)]
    for i in range(m):
        for j in range(n):
            if text1[i] == text2[j]:
                dp[i+1][j+1] = dp[i][j] + 1
            else:
                dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j])
    return dp[m][n]
```