struct OneHandSort {
	std::vector <int> sortShelf(std::vector <int> a) {
		int n = a.size();
		a.emplace_back(-1);
		V<int> ans;
		REP(i, n) {
			if (a[i] == i) continue;
			ans.emplace_back(i);
			std::swap(a[i], a[n]);
			int p = 0;
			REP(j, a.size()) {
				if (a[j] == i) {
					p = j;
					break;
				}
			}
			ans.emplace_back(p);
			std::swap(a[i], a[p]);
			ans.emplace_back(n);
			std::swap(a[p], a[n]);
		}
		return ans;
	}
};