/* problem21.c */

// written by lina <lina.oahz@gmail.com> on Sun Jan 27 12:42:19 SGT 2013

//

#include <stdio.h>

int divisor_sum(int N){

int i;

int sum = 0;

for(i=1; i<N; i++){

if(N%i==0)

sum += i;

}

return sum;

}

int is_amicable(int a, int b){

if(divisor_sum(a) == b && divisor_sum(b) == a && a != b)

return 1;

return 0;

}

int main(){

int i;

int amicableSum = 0;

for(i=1; i<10000; i++){

if(is_amicable(i,divisor_sum(i)))

amicableSum += divisor_sum(i);

}

printf("%d\n",amicableSum);

}