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<cstring>
#include<cstdlib> 
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(cin>>s){
		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));
		}
	}
	cout<<pop()<<endl;
	return 0;
}


