import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        String line = r.readLine();
        int opIndex = 0;
        int[] ops = new int[100];
        for (String elem : line.split(" ")) {
            if (elem.equals("+")) {
                ops[opIndex - 2] += ops[opIndex - 1];
                opIndex--;
            } else if (elem.equals("-")) {
                ops[opIndex - 2] -= ops[opIndex - 1];
                opIndex--;
            } else if (elem.equals("*")) {
                ops[opIndex - 2] *= ops[opIndex - 1];
                opIndex--;
            } else {
                ops[opIndex++] = Integer.parseInt(elem);
            }
        }
        System.out.println(ops[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