import java.util.*;

class Main {
        public static void main(String args[]) {
                int[] stack = new int[1000];
                int i = 0;
                try (Scanner sc = new Scanner(System.in)) {
                        while (sc.hasNext()) {
                                String S = sc.next();
                                if (S.charAt(0) == '+') {
                                        stack[i-2] += stack[i-1];
                                        i--;
                                } else if(S.charAt(0) == '*'){
                                        stack[i-2] *= stack[i-1];
                                        i--;
                                } else if(S.charAt(0) == '-'){
                                        stack[i-2] -= stack[i-1];
                                        i--;
                                } else {
                                        stack[i] = Integer.parseInt(S);
                                        i++;
                                }
                        }
                }
                System.out.println(stack[0]);
        }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz