// #include <cmath>
#include <cstdio>

#define rep( i, n, m ) for (int i = ( n ); i < ( m ); i++)
#define rep_d( i, n, m ) for (int i = ( n ); i < ( m ); i--)

int main( void ){
	int n;
	if(!scanf( "%d", &n ))
		return -1;
	if (n == 1){
		printf( "1\n" );
		return 0;
	}
	int sum = 1 + n;
	int max = n;
	int a;
	for(int i = 2; i < max; i++){
		a = n / i;
		if (n - i * a == 0){
			sum += i;
			sum += a;
			max = a;
		}
	}
	printf("%d\n", sum);
	return 0;
}