#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<cctype>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define LINF (ll)INF*INF
#define MOD 1000000007
#define rep(i,n) for(int i=0;i<(n);i++)
#define loop(i,a,n) for(int i=a;i<(n);i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

#define int ll //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int,int> pii;
typedef vector<pii> vp;

int gcd(int a, int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int lcm(int a, int b){
    return a*b/gcd(a,b);
}

pii f(int i, int j){
    int a = 1000*i/(i+j)+5;
    int b = 1000*j/(i+j)+5;
    return pii(a/10,b/10);
}
#define MAX 10000000000000LL

signed main(void) {
    int n;
    cin >> n;

    if(n%2){//(N+1)/2 × N と N の最大公約数
        n = gcd(n,n);
    }else{//(N+1)×(N/2) と N の最大公約数
        n = gcd(n/2,n);
    }
    int ans = 0;
    for(int i = 1; i*i <= n; i++)if(n%i == 0){
        ans += i;
        if(i*i < n) ans+= n/i;
    }
    cout << ans << endl;
}