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 <stdio.h>
#include <stdlib.h>
#include <string.h>
using namespace std;

int S[1000],top;

void push(int x){
	top++;
	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]=='-'){
			a=pop();
			b=pop();
			push(b-a);
		}else if(s[0]=='*'){
			a=pop();
			b=pop();
			push(a*b);
		}else{
			push(atoi(s));
		}
	}
	
	printf("%d\n",pop());
	
	return 0;
}

