문제
풀이
#include <iostream>
#include <vector>
#define MOD 1000000007
using namespace std;
void solve(void) {
int n; cin >> n;
vector<int> dp(n+1, 1);
for (int i=2; i<=n; i++) {
dp[i] = (dp[i-1] + dp[i-2] + 1) % MOD;
}
cout << dp[n];
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}