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

public class Main {

	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		String[] ary =  br.readLine().split(" ");
		int[] stack = new int[ary.length];
		int stackCount = -1;
		for(int i = 0 ; i < ary.length ; i++){
			if(ary[i].equals("+")){
				stack[stackCount - 1] = stack[stackCount - 1] + stack[stackCount];
				stackCount--;
			}else if(ary[i].equals("-")){
				stack[stackCount - 1] = stack[stackCount - 1] - stack[stackCount];
				stackCount--;
			}else if(ary[i].equals("*")){
				stack[stackCount - 1] = stack[stackCount - 1] * stack[stackCount];
				stackCount--;
			}else{
				stack[++stackCount] = Integer.parseInt(ary[i]);
			}
		}

		System.out.println(stack[stackCount]);
	}

}
/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