150

class Solution {
public:
    int evalRPN(vector<string>& tokens) {
        stack<int> stk;
        for(auto token:tokens){
            if(token == "+" || token == "-" || token  == "*" || token == "/"){
                int op2 = stk.top(); stk.pop();
                int op1 = stk.top(); stk.pop();
                int res;
                if(token == "+") res = op1+op2;
                else if(token == "-") res = op1-op2;
                else if(token == "*") res = op1*op2;
                else if(token == "/") res = op1/op2;
                stk.push(res);
            }
            else{
                int op = stoi(token);
                stk.push(op);
            }
        }
        return stk.top();
    }
};