cleanup

src/agent.rs

@@ -22,7 +22,7 @@ impl Agent for ManualAgent {
             stdin.lock().read_line(&mut input).ok()?;
             let numbers = input
                 .split_whitespace()
-                .map(|i| usize::from_str_radix(i, 10).ok())
+                .map(|i| i.parse::<usize>().ok())
                 .collect::<Option<Vec<usize>>>();
             if let Some(numbers) = numbers {
                 if numbers.len() == 2 {