diff --git a/p2.c b/p2.c
index caaad93..7a9f18e 100644
--- a/p2.c
+++ b/p2.c
@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <sys/types.h>
 
 void main(void) {
   pid_t id_actual, id_padre, pid;