#include #include using namespace atcoder; //using mint = modint1000000007; using mint = modint998244353; //g++ -I/opt/ac-library ./**.cpp using namespace std; using ll = long long; using ull = unsigned long long; //const long long MOD = 1000000007; const long long MOD = 998244353; const long double PI = 3.14159265358979; const long long INF = 1LL<<60; template bool chmax(T &a, const T& b){if(a < b){a = b;return true;}return false;} template bool chmin(T &a, const T& b){if(a > b){a = b;return true;}return false;} #define deb(var) do{cout << #var << " : "; view(var);}while(0) template void view(T e){cout << e << endl;} void view(vector& v){cout << endl;for(auto& s :v){view(s);}cout << endl;} template void view(vector& v){for(auto& e :v){cout << e << " ";}cout << endl;} template void view(vector>& vv){cout << endl;for(auto& v:vv){view(v);}} ll gcd(ll a, ll b){if (b == 0) return a;else return gcd(b, a % b);} ll lcm(ll x,ll y){return ll(x/gcd(x,y))*y;} template using min_priority_queue = priority_queue, greater>; #define all(x) x.begin(), x.end() #define rall(x) x.rbegin(), x.rend() #define int long long int32_t main() { int n; cin >> n; vector a(n); for (int i=0; i> a[i]; } string s; for (int i=1; i'); } int cnt = 0; n--; for (int i=0; i') cnt++; } int cur = 0; int ans = 0; for (int i=0; i') { ans += i - cur; cur++; } } cout << ans << "\n"; }