#include <bits/stdc++.h>

using namespace std;

    long long fib(long long n){
        if(n < 2)
            return n;
        long long head = 0;
        long long tail = 0;
        long long curr = 1;
        for(long long i = 2; i <= n; i++){
            head = tail;
            head %= 1000000007;
            tail = curr;
            tail %= 1000000007;
            curr = tail + head;
            curr %= 1000000007;
        }
        return curr;
    }


int main(){
    long long n;
    cin >> n;
    long long ans = fib(n);
    cout << ans <<endl;
    return 0;
}