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>

int main() {
	char s[100];
	int S[100], top=0, a, b;
	while(scanf("%s", s) != EOF) {
		if(s[0] == '+') {
			a = S[--top];
			b = S[--top];
			S[top++] = a+b;
		} else if(s[0] == '-') {
			a = S[--top];
			b = S[--top];
			S[top++] = b-a;
		} else if(s[0] == '*') {
			a = S[--top];
			b = S[--top];
			S[top++] = b*a;
		} else {
			S[top++] = atoi(s);
		}
	}

	printf("%d\n", S[--top]);
}
