#include <iostream>
#include <math.h>
using namespace std;

int main(){
    int numbers[28123];
    int sindex, cindex = 0;
    for(sindex = 0; sindex < 28123; sindex++)
        numbers[sindex] = 0 - (sindex + 1);
    sindex = 0;
    while(sindex < (int)sqrt(28123)){
        if(cindex >= 28123){
            sindex++;
            cindex = (sindex + 1) * 2 - 1;
        }
        if(sindex + 1 <= (int)sqrt(cindex + 1))
            numbers[cindex] += (sindex + 1) + ((cindex + 1) / (sindex + 1) == (sindex + 1) ? 0: (cindex + 1) / (sindex + 1));
        cindex += sindex + 1;
    }
    cindex = 0;
    for(sindex = 0; sindex < 28123; sindex++)
        if(numbers[sindex] > sindex + 1)
            cindex++;
    int abundants[cindex];
    for(sindex = 0, cindex = 0; sindex < 28123; sindex++)
        if(numbers[sindex] > sindex + 1){
            abundants[cindex] = sindex + 1;
            cindex++;
        }
    sindex = cindex = 0;
    while(sindex < sizeof(abundants) / sizeof(abundants[0])){
        if(cindex >= sizeof(abundants) / sizeof(abundants[0]) || abundants[sindex] + abundants[cindex] - 1 >= 28123){
            sindex++;
            cindex = sindex;
        }
        else{
            numbers[abundants[sindex] + abundants[cindex] - 1] = -1;
            cindex++;
        }
    }
    for(sindex = 0, cindex = 0; sindex < 28123; sindex++)
        if(numbers[sindex] != -1)
            cindex += sindex + 1;
    cout<< cindex << endl;
    system("pause");
    return 0;
}