#include #define ll long long #define pi (acos(-1)) #define rep(i, n) for (unsigned long long i = 0; i < (unsigned long long)(n); ++i) using namespace std; std::vector genprimevec(const unsigned ll N); int main() { int n; cin >> n; if (n == 2) { cout << 1 << endl; return 0; } if (n == 3) { cout << 7 << endl; return 0; } if (n % 2 == 0) { rep(i, (n / 2)) { cout << 1; } cout << endl; return 0; } cout<<7< genprimevec(const unsigned ll N) { std::vector is_prime(N + 1); for (unsigned ll i = 0; i <= N; i++) { is_prime[i] = true; } std::vector P; for (unsigned ll i = 2; i <= N; i++) { if (is_prime[i]) { for (unsigned ll j = 2 * i; j <= N; j += i) { is_prime[j] = false; } P.emplace_back(i); } } return P; }