------
## 最终结论
```python
def max_repetitions(s1, n1, s2, n2):
    len_s1 = len(s1)
    len_s2 = len(s2)
    
    index_s2 = 0
    count_s1 = 0
    count_s2 = 0
    
    while count_s1 < n1:
        for char in s1:
            if char == s2[index_s2]:
                index_s2 += 1
                if index_s2 == len_s2:
                    index_s2 = 0
                    count_s2 += 1
        count_s1 += 1
    
    return count_s2 // n2

# Example usage
s1 = "acb"
n1 = 4
s2 = "ab"
n2 = 2

print(max_repetitions(s1, n1, s2, n2))  # Output: 2
```