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;
    char c[100];
    	while(cin>>c){
		if(c[0]=='+'){
			a=pop();
			b=pop();
			push(a+b);
		}
		else if(c[0]=='-'){
			a=pop();
			b=pop();
			push(b-a);
		}
		else if(c[0]=='*'){
			a=pop();
			b=pop();
			push(a*b);
		}
		else{
			push(atoi(c));
		}
	}
	cout<<pop()<<endl;
    
	return 0;
}

