import sys

deep=int(input().strip())
def f(d):
    res1=0
    res2=0
    p1=0
    p2=0
    if d <=1:
        return 0
    if d==2:
        return 1
    if d>=3:
        res1=3
        p1=2
        res2=4
        p2=4
    for _ in range(3,d):
        p1*=2
        p2*=2
        res1+=p1
        res2+=p2
    return (res1+res2)%(10**9 + 7)
print(f(deep))

思路是递推