n = int(input())
MOD = 1000000007

dp = [[0 for i in range(3)] for j in range(n+1)]
dp[1][1] = 1
#dp[j][i] : j歩目までにi歩連続でケン（j-i歩目がパ, j-i+1~j歩目がケン）
for j in range(1,n):
    dp[j+1][0] = (dp[j][1] + dp[j][2]) % MOD
    dp[j+1][1] = dp[j][0]
    dp[j+1][2] = dp[j][1]

print(sum(dp[n][:]) % MOD)