#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <string.h>
#include <limits.h>


int main(int argc, char *argv[])
{
    struct dirent *ent;
    char filename[PATH_MAX + 1];
    long long sum_size = 0;
    DIR *directory;
    struct stat buf;
    directory = opendir(argv[1]);
    while ((ent = readdir(directory))){
        sprintf(filename, "%s/%s", argv[1], ent -> d_name);
        if (lstat(filename, &buf) ==-1)
            continue;
        if ((S_ISREG(buf.st_mode)) && (!S_ISLNK(buf.st_mode)))
            sum_size += buf.st_size;
    }
    closedir(directory);
    printf("lld\n", sum_size);
    return 0;
}