Avoid function being called every frame (on Start void)

Hi,

well I have a script that is attached to a gameobject the problem is that Start is called every frame (I don't know why) and there I have a function that adds some information to a Dictionary, and every second is created a new entry on the dictionary.

How can I call the function only one time?

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class Ammo {
 
     public float ammoboxSize;
 
 }
 
 public class CurWeapons {
 
     public static Dictionary<string, Ammo> ammoLib = new Dictionary<string, Ammo>();
 
     public static void SetNewWeapon(string str, Ammo lib) {
         Debug.Log ("Key " + str + " added.");
         ammoLib.Add(str, lib);
     }
 
     public static Ammo RetrieveInfo(string name) {
         return ammoLib[name];
     }
 
     public static void ChangeAmmo(string name, float bullets) {
 
         Ammo tempAmmoPreset = ammoLib[name];
         tempAmmoPreset.ammoboxSize = bullets;
 
         ammoLib[name] = tempAmmoPreset;
 
     }
 
 }
 
 public class AmmoScript : MonoBehaviour {
 
     public float ammo_boxSize = 32;
 
     // Use this for initialization
     void Start () {
         Ammo ammoPreset;
 
         ammoPreset = new Ammo();
         ammoPreset.ammoboxSize = ammo_boxSize;
         CurWeapons.SetNewWeapon(transform.name, ammoPreset);
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 }

That code is used to determine the capacity of a weapon, and sets the number of bullets that It have.

Thanks. Bye.