```go
package main

import (
	"fmt"
)

func main() {
	var s string
	fmt.Scan(&s)

	stack := []int{}

	for _, ch := range s {
		if ch >= '0' && ch <= '9' {
			stack = append(stack, int(ch-'0'))
		} else if ch == '+' {
			n := len(stack)
			a, b := stack[n-2], stack[n-1]
			stack = stack[:n-2]
			stack = append(stack, a+b)
		} else if ch == '*' {
			n := len(stack)
			a, b := stack[n-2], stack[n-1]
			stack = stack[:n-2]
			stack = append(stack, a*b)
		}
	}

	fmt.Println(stack[len(stack)-1])
}
```