#pragma comment(linker, "/stack:247474112")
//#pragma GCC optimize("Ofast")

#include<bits/stdc++.h>

using namespace std;

#define     pii             pair<int ,int>
#define     ff              first
#define     ss              second
#define     pb(x)           push_back(x ) 
#define     mp              make_pair
#define     sz(x)           x.size()
#define     clr(x)          x.clear()
#define     mem(x ,y)       memset(x , y , sizeof x )
#define     all(a )         a.begin() , a.end()
#define     endl            "\n"
#define     si(x )          scanf("%d", &x);
#define     sii(x,y )       scanf("%d%d", &x,&y);
#define     siii(x,y ,z)    scanf("%d%d%d ", &x,&y , &z);
#define     rep(i ,n )      for(int i = 0 ; i < n ; i++ )
#define     repi(i ,n )     for(int i = 1 ; i <= n ; i++ )
#define     forn(i ,x,n )   for(int i = x ; i <= n ; i++ )
#define     repit(i, c)     for( __typeof((c).begin()) i = (c).begin(); i != (c).end();++i )
#define     dbg(args...)    do {   cerr << #args << ' ' ;  print(args); } while(0); cerr<< endl ;

typedef long long ll  ;
typedef unsigned long long  ull ;
typedef vector<int> vi  ;

const int  mod = 1e9+7 ;
const int inf = 1e9  ;
const long long  infL = 1e18 ;

ll setbit(ll n, int pos  ) { return n = n|(1LL<< pos) ; }
int resetbit(int n,int pos ) {  return n =  n & ~(1<<pos ); }
bool checkbit(ll n,int pos ) { return (bool ) (n& (1LL<<pos))  ; }

template < typename T > T mul(T x, T y   ) { x %= mod ; y %= mod ; return (x*y)%mod  ;  }
template < typename T > T add(T x, T y  ) { x %= mod ; y %= mod ; return (x+y)%mod ;  }
template < typename T > T modPow(T x, T k ,T mod ) { if(k == 0 ) return 1; if(k&1  ) { return ( (x%mod)*modPow(x,k-1, mod )%mod )%mod ; } else { T ret = modPow(x,k/2 , mod ) ; ret %= mod ; return (ret*ret )%mod; } }
template < typename T > T ext_gcd(T num1 , T num2, T &X , T &Y ) { T r2,r1, q2, q1 , x2, x1, y2 ,y1 , x,  y, r   ; x2 = 1; y2 = 0;  x1 = 0; y1 = 1; for( r2 =num1 ,r1 = num2 ;r1 != 0 ; y2 = y1, y1 = y,x2 = x1 ,x1 = x ,r2 = r1, r1 = r) {q1 = r2/r1; x = x2 - q1*x1; y = y2 - q1*y1; r = r2%r1 ; } X = x2 ; Y = y2 ; return r2 ;  }
template < typename T > T modInv( T x , T m ) {  return modPow(x,m-2 , m) ; }  // long long ret, t ;// ext_gcd( x, m ,ret ,t  ) ;// ret %= m ;// if(ret<0) ret += m  ; // return ret;}
template < typename T > void print(const T& v) {    cerr << v << ' ' ;}
template < typename T1, typename... T2 > void print( const T1& first, const T2&... rest ){ print(first); print(rest...) ;}

// debuging ...
template < typename F, typename S >
ostream& operator << ( ostream& os, const pair< F, S > & p ) {
    return os << "[ " << p.first << ", " << p.second << " ]";
}

template < typename T >
ostream &operator << ( ostream & os, const vector< T > &v ) {
    os << "[ "; rep(i , sz( v)  )  os << v[i] << ' ' ; return os << " ]" ; 
}

template < typename T >
ostream &operator << ( ostream & os, const set< T > &v ) {
    os << "[ "; repit(it,  v  )  os << *it << ' ' ; return os << " ]" ; 
}

template < typename T >
ostream &operator << ( ostream & os, const multiset< T > &v ) {
    os << "[ "; repit(it,  v  )  os << *it << ' ' ; return os << " ]" ; 
}

//////////

#ifndef ONLINE_JUDGE 

#define mylog(...)   printf( __VA_ARGS__ )
#else 
#define mylog(...)   /****nothing****/
#endif


//int dx[] = {0 , 0 ,+1, -1 } ;
//int dy[] = {-1, +1,0 , 0 };
 
// code from here
const int M = 2e6+7 ;  
const int mx = (int)(1e4) +1 ; 
//const ll N = 1e7+5 ;
 
void solve() {
    ll n,ans = 0 , t ; 
    cin >>n ; 
    ans = 0; 
   
    for(ll i=1; i*i <=n; i++) {
        if(n%i == 0) {
            if(i> 1 and n/(i-1) == n%(i-1) ){

                ans += (i-1);
              //  dbg( i-1) ;
            } 

            if(n/i!= i) {
                t = n/i ; 
                if(n/(t-1) == n%(t-1) ){
                    ans += (t-1) ;
                  //  dbg(t-1 ) ;
                }

            }

        }


    }
    cout << ans << endl ;

    // // =50;
    // for(ll i=1; i<=n;i++  ) {
    //     // if(n%i== 0)  {
    //     //     dbg("bang "  ,i) ;
    //     // }
    //     if(n/i == n%i ) {
    //         dbg(i ,n/i , n %i) ; 
    //     }

    //   //  if(n%i==0 ) cout<< endl; 
    // } 


}
int main() { 
    #ifndef ONLINE_JUDGE
         //freopen("in.txt", "r", stdin);
        //freopen("out.txt", "w", stdout);
    #endif 
    //ios::sync_with_stdio(false);  cin.tie(0); cout.tie(0);
    
    int t=1; 
    while(t--) solve() ;

    return 0 ;
}

 




















Measured memory_bytes: 256