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 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;
}