package main

import (
    "fmt"
)

const mod float64 = 1e9+7

func main() {
    var h int
    fmt.Scan(&h)
    cnt := 0
    if h > 1 {
        cnt = 3 * getCnt2(h-1) - 5
        cnt = cnt%int(mod)
    }
    
    fmt.Println(cnt)
}

func getCnt2(n int) int {
    result := 1
    for i:=1; i<= n; i++ {
        result*=2
        result%=int(mod)
    }

    return result
}