#include <iostream>
#include <vector>

using namespace std;

int countStableSubsegmentsBrute(const vector<int>& capacity) {
    int n = capacity.size();
    int count = 0;

    for (int l = 0; l < n; ++l) {
        long long midSum = 0;
        for (int r = l + 1; r < n; ++r) {
            if (r - l >= 2) { // length ≥ 3
                midSum += capacity[r - 1];
                if (capacity[l] + capacity[r] == midSum) {
                    count++;
                }
            } else {
                midSum += capacity[r - 1];
            }
        }
    }

    return count;
}

int main() {
    vector<int> capacity = {9, 3, 3, 3, 9};
    cout << "Stable subsegments: " << countStableSubsegmentsBrute(capacity) << endl; // Output: 2
    return 0;
}