brute force
```python3 []
class Solution:
    def minimumPairRemoval(self, nums: List[int]) -> int:
        i = 0
        while nums != list(sorted(nums)):
            i += 1
            k = 0
            b = nums[0] + nums[1]
            for j in range(len(nums)-1):
                if nums[j] + nums[j+1] < b:
                    b = nums[j] + nums[j+1]
                    k = j
            nums[k] = b
            del nums[k+1]
        return i
```
['Python3']