diff --git a/.gitea/workflows/build_and_run.yml b/.gitea/workflows/build_and_run.yml
index 0cf847d..a76732d 100644
--- a/.gitea/workflows/build_and_run.yml
+++ b/.gitea/workflows/build_and_run.yml
@@ -11,7 +11,7 @@ jobs:
     name: Challenge for day
     strategy:
       matrix:
-        day_number: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
+        day_number: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25]
     runs-on: rust-bookworm
     steps:
       - name: Check out repository code
diff --git a/day25/Cargo.toml b/day25/Cargo.toml
new file mode 100644
index 0000000..e5f4cc3
--- /dev/null
+++ b/day25/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "day25"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/day25/src/main.rs b/day25/src/main.rs
new file mode 100644
index 0000000..6577835
--- /dev/null
+++ b/day25/src/main.rs
@@ -0,0 +1,68 @@
+use std::{env, fs};
+
+fn read_input(path: &str) -> String {
+    fs::read_to_string(path).expect("Cannot read file.")
+}
+
+fn parse_input(input: &str) -> (Vec<Vec<u8>>, Vec<Vec<u8>>) {
+    let mut keys = Vec::new();
+    let mut locks = Vec::new();
+
+    let mut height = 0;
+    let mut x = vec![5; 5];
+    let mut is_key = false;
+    for line in input.lines() {
+        if line.is_empty() {
+            height = 0;
+            continue;
+        }
+
+        if height == 0 {
+            is_key = line.starts_with(".");
+        } else if height == 6 {
+            if is_key {
+                keys.push(x.iter().map(|i| 5 - i).collect());
+            } else {
+                locks.push(x);
+            }
+            x = vec![5; 5];
+        } else {
+            for (i, c) in line.chars().enumerate() {
+                if x[i] == 5 && ((is_key && c == '#') || (!is_key && c == '.')) {
+                    x[i] = height - 1;
+                }
+            }
+        }
+        height += 1;
+    }
+
+    (keys, locks)
+}
+
+fn part_1(keys: &Vec<Vec<u8>>, locks: &Vec<Vec<u8>>) -> u32 {
+    let mut combinations = 0;
+    for key in keys {
+        for lock in locks {
+            for i in 0..5 {
+                if key[i] + lock[i] > 5 {
+                    break;
+                }
+                if i == 4 {
+                    combinations += 1;
+                }
+            }
+        }
+    }
+
+    combinations
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    for arg in args.iter().skip(1) {
+        let input = read_input(&arg);
+        let (keys, locks) = parse_input(&input);
+        println!("[{}]", &arg);
+        println!("\t[Part 1] => Answer is '{}'.", part_1(&keys, &locks));
+    }
+}