#include #include #include #include using namespace std; typedef long long ll; typedef vector vint; typedef pair pint; typedef vector vpint; #define rep(i,n) for(int i=0;i<(n);i++) #define reps(i,f,n) for(int i=(f);i<(n);i++) #define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++) #define all(v) (v).begin(),(v).end() #define pb push_back #define mp make_pair #define fi first #define se second #define chmax(a, b) a = (((a)<(b)) ? (b) : (a)) #define chmin(a, b) a = (((a)>(b)) ? (b) : (a)) const int MOD = 1e9 + 7; const int INF = 1e9; int main(void){ ll n; cin >> n; ll ma; if(n % 2 == 0){ ma = n / 2; }else{ ma = n; } ll ans = 1 + ma; ll tmp = ma; for (int i = 2; i * i <= ma + 10; ++i){ if(ma % i == 0){ // printf("%d\n", i); ans += i; while(tmp % i == 0){ tmp /= i; } } } //(sqrt(n)以上の素数は1or0) if(tmp > 1 && tmp != ma) ans += tmp; printf("%lld\n", ans); return 0; }