#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>

pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER;
long long int j=0;
int sum=0;


void* child_fn ( void* arg ) {
   pthread_mutex_lock(&mut);
   while(j<1000000000) {
   sum=(sum+j*j) %1024;
   j++;
   }
   pthread_mutex_unlock(&mut);
   return NULL;
}

int main (int argc, char **argv) {
   int i,a;
   a=atoi(argv[1]);
   pthread_t child;
   for(i=0;i<a;i++) pthread_create(&child, NULL, child_fn, NULL);
   pthread_join(child, NULL);
   printf("%d\n", sum);
   return 0;
}