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#include<iostream>
using namespace std;
class RPN
{
	int a[999];//数字
	int top = 999;
public:
	RPN()
	{
		for (int i = 0;i <999; i++)
			a[i] = { 0 };
	}
	~RPN(){}
	void push(int x)
	{
		top--;
		a[top] = x;
	}
	int pop()
	{//删除栈顶数据;
		char x = a[top];
		top++;
		return x;
	}
	bool empty()
	{
		if (top == 999)
			return 1;
		return 0;
	}
	int Val(char *data)
	{//输入进来字符串
		//然后判断，是数字还是符号，数字进栈，符号出栈
		while (*data != '\0')
		{
			char ch = *data;
			int z=0;
			if (ch >= '0' && ch <= '9')
			{
				push(ch-'0');
			}
			else
			{
				int x, y;
				x = pop();
				y = pop();
				switch (ch)
				{
				case'+':
					z = x + y;
					break;
				case'-':
					z = x - y;
					break;
				case'*':
					z = x * y;
					break;
				case'/':
					z = x / y;
					break;
				case'%':
					z = x - y;
					break;
				default:
					break;
				}
				push(z);
			}
			data++;
		}
		if (empty() == false)
		{
			int i = a[998];
			return i;
		}
		return 0;
	}
};
int main()
{
	char data[999];
	cin >> data;
	RPN r;
	cout<<r.Val(data)<<endl;
	return 0;
}复制