diff --git a/2025/Cargo.lock b/2025/Cargo.lock
index e5cb7a3..cd1117f 100644
--- a/2025/Cargo.lock
+++ b/2025/Cargo.lock
@@ -130,6 +130,21 @@ dependencies = [
  "tracing-subscriber",
 ]
 
+[[package]]
+name = "day-03"
+version = "0.1.0"
+dependencies = [
+ "divan",
+ "itertools",
+ "miette",
+ "nom",
+ "rstest",
+ "test-log",
+ "thiserror",
+ "tracing",
+ "tracing-subscriber",
+]
+
 [[package]]
 name = "divan"
 version = "0.1.21"
diff --git a/2025/daily-template/src/part1.rs b/2025/daily-template/src/part1.rs
index 0a00e1f..1639d01 100644
--- a/2025/daily-template/src/part1.rs
+++ b/2025/daily-template/src/part1.rs
@@ -1,9 +1,7 @@
-use miette::Result;
-
 #[tracing::instrument]
 #[allow(clippy::missing_panics_doc)]
 #[allow(clippy::missing_errors_doc)]
-pub fn process(input: &str) -> Result<usize> {
+pub fn process(input: &str) -> miette::Result<usize> {
     todo!("day xx - part 1");
     Ok(0)
 }
@@ -13,7 +11,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_process() -> Result<()> {
+    fn test_process() -> miette::Result<()> {
         let input = "";
         todo!("haven't built test yet");
         let result = 0;
diff --git a/2025/day-03/src/part1.rs b/2025/day-03/src/part1.rs
index 0a00e1f..184e40c 100644
--- a/2025/day-03/src/part1.rs
+++ b/2025/day-03/src/part1.rs
@@ -1,11 +1,75 @@
-use miette::Result;
+use itertools::Itertools;
+use std::{ops::Add, str::FromStr};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+struct Joltage(u8);
+
+impl Add for Joltage {
+    type Output = Self;
+    fn add(self, rhs: Self) -> Self::Output {
+        Self(self.0 * 10 + rhs.0)
+    }
+}
+
+impl Add for &Joltage {
+    type Output = Joltage;
+    fn add(self, rhs: Self) -> Self::Output {
+        Joltage(self.0 * 10 + rhs.0)
+    }
+}
+
+impl From<Joltage> for usize {
+    fn from(value: Joltage) -> Self {
+        Self::from(value.0)
+    }
+}
+
+impl TryFrom<char> for Joltage {
+    type Error = String;
+    fn try_from(ch: char) -> std::result::Result<Self, Self::Error> {
+        let s = ch.to_string();
+        let value = s.parse::<u8>().map_err(|e| e.to_string())?;
+        Ok(Self(value))
+    }
+}
+#[derive(Debug, Clone)]
+struct Bank(Vec<Joltage>);
+
+impl Bank {
+    fn get_max_value(&self) -> usize {
+        let mut clone = self.0.clone();
+        clone.truncate(self.0.len() - 1);
+        let max1 = clone.iter().max().unwrap();
+        let (pos1, _) = self.0.iter().find_position(|&x| x == max1).unwrap();
+        let list = self.0.clone().split_off(pos1 + 1);
+        let max2 = list.iter().max().unwrap();
+        (max1 + max2).into()
+    }
+}
+
+impl FromStr for Bank {
+    type Err = String;
+    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
+        let bank = s
+            .trim()
+            .chars()
+            .map(Joltage::try_from)
+            .collect::<Result<Vec<_>, String>>()?;
+
+        Ok(Self(bank))
+    }
+}
 
 #[tracing::instrument]
 #[allow(clippy::missing_panics_doc)]
 #[allow(clippy::missing_errors_doc)]
-pub fn process(input: &str) -> Result<usize> {
-    todo!("day xx - part 1");
-    Ok(0)
+pub fn process(input: &str) -> miette::Result<usize> {
+    let banks = input
+        .lines()
+        .map(|line| Bank::from_str(line).unwrap())
+        .map(|bank| bank.get_max_value())
+        .sum();
+    Ok(banks)
 }
 
 #[cfg(test)]
@@ -13,10 +77,13 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_process() -> Result<()> {
-        let input = "";
-        todo!("haven't built test yet");
-        let result = 0;
+    fn test_process() -> miette::Result<()> {
+        let input = "987654321111111
+811111111111119
+234234234234278
+818181911112111
+";
+        let result = 357;
         assert_eq!(process(input)?, result);
         Ok(())
     }