c#include <bits/stdc++.h> using namespace std; long long dp[51]; int main(){ cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(false); int N; cin >> N; if(N < 2){ cout << 1 << "\n"; return 0; } dp[0] = 1; dp[1] = 1; for(int i = 2; i <= N; i++){ dp[i] = dp[i - 1] + dp[i - 2] + 1; dp[i] %= 1000000007; } cout << dp[N] << "\n"; return 0; }