#include<iostream>

int main(){
    int n;
    std::cin >> n;

    long long k = 1, kk = 1, kkk = 1;
    if(n == 1) {
        std::cout << 1 << std::endl;
        return 0;
    }else if(n == 2 || n == 3){
        std::cout << 2 << std::endl;
        return 0;
    }

    n -= 3;
    for(int i = 0;i < n; ++i){
        int temp = k;
        k = kk + kkk;
        kkk = kk;
        kk = temp;
        k %= 1000000007;
    }

    std::cout << (k + kk) % 1000000007 << std::endl;
    return 0;
}