Easy Python Solution
IntuitionApproachComplexity
Time complexity: O(n^3)

Space complexity: O(1)
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity: O(n^3)
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity: O(1)
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```python3 []
class Solution:
    def minimumSum(self, nums: List[int]) -> int:
        res = float('inf')

        for l in range(len(nums) - 2):
            for m in range(l + 1, len(nums) - 1):
                for r in range(m + 1, len(nums)):
                    if nums[l] < nums[m] and nums[m] > nums[r]:
                        res = min(res, nums[l] + nums[m] + nums[r])

        return -1 if res == float('inf') else res
```
['Array', 'Python3']