Notes

Template in C

Constraints

2 ≤ the number of operands in the expression ≤ 100
1 ≤ the number of operators in the expression ≤ 99
-1 × 109 ≤ values in the stack ≤ 109

Input

An expression is given in a line. Two consequtive symbols (operand or operator) are separated by a space character.

You can assume that +, - and * are given as the operator and an operand is a positive integer less than 106

Output

Print the computational result in a line.

Examples

Input

1 2 +


Output

3


Input

1 2 + 3 4 - *


Output

-3
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
int top,s[1000];
void push(int x){
	s[++top]=x;
}
int pop()
 { top--;
  return s[top+1];
}

int main()
{
	int a,b;
	top=0;
	char s[100];
	while(scanf("%s",s)!=EOF){
		if(s[0]=='+'){a=pop();
		b=pop();push(a+b);}
		else if(s[0]=='-'){
		b=pop();a=pop();
		push(a-b);
		}
		else if(s[0]=='*'){
			a=pop();b=pop();
			push(a*b);
		}else{push(atoi(s));//atoi(s)将字符串形式的数字转换成整型数字// 
		}
	}
cout<<pop()<<endl;
return 0;
}
