n=int(input())
v=[0]*(n+2)
v[0]=1
v[1]=2
v[2]=2
mod=10**9+7
if n<4:
    print(v[n-1])
else:
    for i in range(3,n):
        v[i]=(v[i-2]+v[i-3])%mod
    print(v[-1])