The top 3 Items to bring in my opinion

 Being lost in the cold mountains can be quite risky as there are many possibilities that may occur. Applying that I already do have warm clothes and a jacket to keep me warm at the least. Items that are used for navigation and food rations may be also good to be able to survive. The first item I would bring is a device that is able to dial in an emergency call, as there is no signal on the mountains. Since emergency calls do not require a network signal. So that it is accessible for me to call the police or mountain rescue teams. The second item I would bring is a flashlight that has strong brightness or light capability as it would be easier for people to see or spot me. As it would link back to the first item that I need for me to let the group know of where my exact location is. The third item I would bring is some rations and water. Maybe without prior knowledge, some fruits or living beings in the mountains may prove not edible or dangerous. Bringing in good food and water enough to sustain until rescue arrives is essential for me. For there is no telling of when the rescue team may arrive. There may be other factors that would change my lists as I still do not know of the possibilities I may encounter whilst be in the mountains. Other things that could prove potentially dangerous or harmful might come across to me. Such as wild animals and natural hazards. Overall keeping in touch with the people who can help me get back to safety is my most prioritized in my opinion as chances are. There is no knowing what will happen and what will I encounter being lost in the mountains.