Index: aoc2015.c
==================================================================
--- aoc2015.c
+++ aoc2015.c
@@ -1,10 +1,23 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include "aocdailies.h"
 #include "aocutils.h"
+
+void aoc201504(char *data, size_t len) {
+    (void)len; // unused argument
+    unsigned extra = 1;
+    char longkey[128];
+    for (;;) {
+        sprintf(longkey, "%s%u", data, extra);
+        //md5(longkey);
+        if (1) break;
+        extra++;
+    }
+    printf("Follow your key with %u to obtain five zeroes\n", extra);
+}
 
 struct House {
     int row, col;
 };
 

Index: aoc2024.c
==================================================================
--- aoc2024.c
+++ aoc2024.c
@@ -4,10 +4,15 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "aocdailies.h"
 #include "aocutils.h"
+
+void aoc202406(char *data, size_t len) {
+    (void)data;
+    (void)len;
+}
 
 static int ppcmp(unsigned a, unsigned b, unsigned (*r)[2], size_t nr) {
     for (size_t k = 0; k < nr; k++) {
         if ((a == r[k][0]) && (b == r[k][1])) return -1;
         if ((a == r[k][1]) && (b == r[k][0])) return 1;

Index: aocdailies.c
==================================================================
--- aocdailies.c
+++ aocdailies.c
@@ -4,10 +4,11 @@
 aocfunc *aocselect(unsigned y, unsigned d) {
     aocfunc *p;
     switch (y * 100 + d) {
         default: p = NULL; break;
 
+        case 202406: p = aoc202406; break;
         case 202405: p = aoc202405; break;
         case 202404: p = aoc202404; break;
         case 202403: p = aoc202403; break;
         case 202402: p = aoc202402; break;
         case 202401: p = aoc202401; break;
@@ -32,14 +33,14 @@
         case 201509: p = aoc201509; break;
         case 201508: p = aoc201508; break;
         case 201507: p = aoc201507; break;
         case 201506: p = aoc201506; break;
         case 201505: p = aoc201505; break;
-        case 201504: p = aoc201504; break;
         #endif
+        case 201504: p = aoc201504; break;
         case 201503: p = aoc201503; break;
         case 201502: p = aoc201502; break;
         case 201501: p = aoc201501; break;
 
     }
     return p;
 }

Index: aocdailies.h
==================================================================
--- aocdailies.h
+++ aocdailies.h
@@ -4,10 +4,11 @@
 #include <stddef.h>
 
 typedef void aocfunc(char *, size_t);
 aocfunc *aocselect(unsigned, unsigned);
 
+aocfunc aoc202406;
 aocfunc aoc202405;
 aocfunc aoc202404;
 aocfunc aoc202403;
 aocfunc aoc202402;
 aocfunc aoc202401;
@@ -32,12 +33,12 @@
 aocfunc aoc201509;
 aocfunc aoc201508;
 aocfunc aoc201507;
 aocfunc aoc201506;
 aocfunc aoc201505;
-aocfunc aoc201504;
 #endif
+aocfunc aoc201504;
 aocfunc aoc201503;
 aocfunc aoc201502;
 aocfunc aoc201501;
 
 #endif