Add math.Int input class

Author: Ben Keller

src/main/java/math/Int.java

@@ -0,0 +1,23 @@
+package math;
+
+public class Int {
+
+  private final int value;
+
+  public String toString() {
+    return Integer.toString(value);
+  }
+
+  private Int() {
+    this.value = 0;
+  }
+
+  public Int(int value) {
+    this.value = value;
+  }
+
+  public Int add(Int other) {
+    return new Int(this.value + other.value);
+  }
+
+}