#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long LL; typedef unsigned long long ULL; #define MEM(a,b) memset((a),(b),sizeof(a)) const LL INF = 1e9 + 7; const int N = 5e5 + 10; int main() { //freopen("input.txt", "r", stdin); //freopen("output.txt", "w", stdout); LL n; cin >> n; n += (n & 1) ^ 1; cout << n << endl; return 0; }