# 1 1 2 3 5 8 13
def feibo(n):
    if n==1 or n==2:
        return 1
    if list[n]!=0:
        return list[n]
    else:
        a=(feibo(n-1)+feibo(n-2))%(1000000007)
        list[n]=a
        return a

n=int(input())

list=[0]*(n+1)

b=feibo(n)
print(b)