def test1(nums, target):
    nums.sort()  #先排序
    left,right = 0,len(nums)-1
    n = 0
    while(left < right):
        if(nums[left] + nums[right] > target):
            right -= 1
        else:
            n += (right - left)
            left += 1
    return n%(10**9+7)

nums = [2,2,1,9]
target = 10
print(test1(nums,target))