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 "bits/stdc++.h"
using namespace std;
int st[100];
int ptr=0;
int pop(void) {
	return st[--ptr];
}
void push(int op) {
	st[ptr++]=op;
}
int main() {
	char s[10];
	while(scanf("%s",s)!=EOF) {
		if(isdigit(s[0])) {
			int op;
			sscanf(s,"%d",&op);
			push(op);
		}else {
			int op2=pop(),op1=pop();
			switch(s[0]) {
			case '+':push(op1+op2);break;
			case '-':push(op1-op2);break;
			case '*':push(op1*op2);break;
			}
		}
	}
	printf("%d\n",pop());
}