#include <bits/stdc++.h> using namespace std; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; vector<int> a(n); for (auto& x : a) cin >> x; int ans = 0; for (int i = 0; i < n - 1; i++) { if (a[i] < a[i+1] + 2) continue; int j = i + 1; while (j < n && a[i] >= a[j] + 2) j++; if (j >= n) continue; while (j > i + 1) { swap(a[j], a[j-1]); ans++; j--; } } cout << ans; }