#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int top, S[1000];

void push(int);
int pop(void);

int main()
{
  int x, y;
  char s[100];
  top = 0;
  
  while( scanf("%s", s) != EOF )
    {
      if ( s[0] == '+' )
	{
	  x = pop();
	  y = pop();
	  push(x+y);
	}
      else if ( s[0] == '-' )
	{
	  y = pop();
	  x = pop();
	  push(x-y);
	}
      else if ( s[0] == '*' )
	{
	  x = pop();
	  y = pop();
	  push(x*y);
	}
      else
	{
	  x = atoi(s);
	  push(x);
	}
    }

      printf("%d\n",pop());
  
  return 0;
}

void push(int x)
{
  S[++top] = x;
}

int pop(void)
{
  top--;
  return S[top+1];
}

