/* Author:zeke pass System Test! GET AC!! */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using ll = long long; using ld = long double; using namespace std; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define all(x) (x).begin(), (x).end() #define rep3(var, min, max) for (ll(var) = (min); (var) < (max); ++(var)) #define repi3(var, min, max) for (ll(var) = (max)-1; (var) + 1 > (min); --(var)) #define Mp(a, b) make_pair((a), (b)) #define F first #define S second #define Icin(s) \ ll(s); \ cin >> (s); #define Scin(s) \ ll(s); \ cin >> (s); template bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; } template bool chmin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; } typedef pair P; typedef vector V; typedef vector VV; typedef vector

VP; ll MOD = 1e9 + 7; ll INF = 1e18; const int N = pow(10, 7); vector isp(N + 1, true); void sieve() { isp[0] = false; isp[1] = false; for (int i = 2; pow(i, 2) <= N; i++) { if (isp[i]) for (int j = 2; i * j <= N; j++) isp[i * j] = false; } } //N以下の整数をふるってくれます long long GCD(long long a, long long b) { if (b == 0) return a; return GCD(b, a % b); } long long LCM(long long a, long long b) { return a * b / GCD(a, b); } V vec; ll n, k; bool judge(ll x){ ll c=0; ll prev = x; while(1){ ll f = lower_bound(all(vec), x) - vec.begin(); if(f==5) break; prev = vec[f]; c++; } return c <= k; } int main() { cin.tie(0); ios::sync_with_stdio(false); ll n; cin>>n; if(n>=3){ if(n%2==1){ cout << n << endl; }else{ ll k=(n-1)*n/2; cout<