import java.util.ArrayDeque;

public class Solution {
    public int evalRPN(String[] tokens) {
        ArrayDeque<Integer> s=new ArrayDeque<>();
        for(int i=0;i<tokens.length;i++){
            try{
                int num=Integer.parseInt(tokens[i]);
                s.push(num);
            }
            catch (Exception e){
                int b=s.pop();
                int a=s.pop();
                s.push(get(a,b,tokens[i]));
            }
        }
        return s.pop();

    }
    int get(int a,int b,String operator){
        switch (operator){
            case "+":
                return a+b;
            case "-":
                return a-b;
            case "*":
                return a*b;
            case "/":
                return a/b;
            default:
                return 0;
        }
    }
}