#include <bits/stdc++.h>
using namespace std;
//Code tot hon => chay nhanh hon, it vong lap hon
int tonguoc2(int n){
int sum = 0;
for(int i = 1; i <= sqrt(n); i++){
if(n % i == 0){
sum += i;
// i => n / i
if(i != n / i){
sum += n / i;
}
}
}
return sum;
}
int demuoc(int n){
int ans = 0;
for(int i = 1; i <= sqrt(n); i++){
if(n % i == 0){
++ans;
if(i != n / i){
++ans;
}
}
}
return ans;
}
int main(){
int n; cin >> n;
cout << tonguoc2(n) << endl;
}
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