#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>


int main(int argc, char * argv[]) {

    for (size_t i = 1; i < argc; i++) {

        struct stat file_stat;
        if (stat(argv[i], &file_stat)) {
            printf("-1");
            return 1;
        }

        off_t file_size = file_stat.st_size;
        if (!file_size) {
            printf("0\n");
            break;
        }
        size_t data_len = file_size / sizeof(char);

        int file = open(argv[i], O_RDONLY, 0);
        if (file == -1) {
            printf("-1");
            return 1;
        }

        void *mapped = mmap(
                NULL,
                file_size,
                PROT_READ,
                MAP_PRIVATE,
                file,
                0
        );

        char * data = mapped;
        size_t j = 0;
        unsigned long long num_of_lines = 0;
        while(data[j] != EOF) {
            if (data[j] == '\n')
                num_of_lines++;
            j++;
        }
        if (data[j - 1] != '\n')
            num_of_lines++;
        printf("%llu\n", num_of_lines);
        i++;
        munmap(mapped, file_size);
        close(file);
    }
    return 0;
}