#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <netdb.h>

unsigned int ip2int(const char *s)
{
	int ip[4];
	sscanf(s, "%d.%d.%d.%d", ip, ip + 1, ip + 2, ip + 3);
	return ip[0] << 24 | ip[1] << 16 | ip[2] << 8 | ip[3];
}

int main(int argc, char *argv[])
{
	if (argc < 2) {
		perror("need ip address string");
		exit(1);
	}

	printf("%X\n", ip2int(argv[1]));

	return 0;
}