Index: aoc2025.c
==================================================================
--- aoc2025.c
+++ aoc2025.c
@@ -19,17 +19,25 @@
 /* === aoc202505 =======================================================
 ===================================================================== */
 struct Range {
     long long unsigned lo, hi;
 };
+
+int ascending(const void *a, const void *b) {
+    const struct Range *aa = a, *bb = b;
+    if (aa->lo < bb->lo) return -1;
+    if (aa->lo > bb->lo) return 1;
+    return 0;
+}
 
 void aoc202505(char *data, size_t len) {
     (void)len; // unused argument
     struct Range r[200] = {0};
     size_t nr = 0;
     char *err;
     for (;;) {
+        // read ranges
         char *minus = strchr(data, '-');
         if (!minus) break;
         *minus = 0;
         r[nr].lo = strtoull(data, &err, 10);
         *minus++ = '-';
@@ -39,13 +47,13 @@
         *enter++ = '\n';
         data = enter;
     }
     unsigned fresh = 0;
     for (;;) {
+        // read and process single entries
         long long unsigned item = strtoull(data, &err, 10);
         if (err[0] != '\n') break;
-        if (item == 0) break;
         data = err + 1;
         for (size_t k = 0; k < nr; k++) {
             if ((r[k].lo <= item) && (item <= r[k].hi)) {
                 fresh++;
                 break;
@@ -52,11 +60,25 @@
             }
         }
     }
     printf("There are %u fresh items.\n", fresh);
 
-    // pause for brain storming pause
+    qsort(r, nr, sizeof *r, ascending);
+    #if 0
+    for (;;) {
+        int mergecount = 0;
+        for (size_t k = 1; k < nr, k++) {
+            for (size_t kk = 0; kk < k; kk++) {
+                mergecount += merge(r, kk, k) {
+                    mergecount++;
+                    nr--;
+                }
+            }
+        }
+        if (mergecount == 0) break;
+    }
+    #endif
 }
 
 /* === aoc202504 =======================================================
 ===================================================================== */
 static unsigned evolve(struct RectangularMap *rm, unsigned src) {