#pragma region header #include using namespace std; #define int long long #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define rep1(i, n) for (int i = 1; i <= (int)(n); i++) #define rev(i, n) for(int i = (int)(n - 1); i >= 0; i--) #define rev1(i, n) for(int i = (int)(n); i > 0; i--) #define pb push_back #define all(v) (v).begin(), (v).end() #define resort(v) sort((v).rbegin(), (v).rend()) #define vi vector #define vvi vector> #define vc vector #define vvc vector> #define vb vector #define vvb vector> using ll = long long; using P = pair; /* ----------------よく使う数字や配列----------------- */ int dx[] = {1,0,-1,0}; int dy[] = {0,1,0,-1}; constexpr ll mod = 1e9+7; constexpr int inf = INT32_MAX/2; constexpr ll INF = LLONG_MAX/2; constexpr long double eps = DBL_EPSILON; constexpr long double pi = 3.141592653589793238462643383279; /* ----------------------end----------------------- */ /* --------------------テンプレート------------------ */ template inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } /* ----------------------end----------------------- */ /* --------------------ライブラリ-------------------- */ ll fact(int i) { //階乗 if (i == 0) return 1; return (fact(i - 1)) * i % mod; } ll gcd(ll a, ll b) { //最大公約数 if(b == 0) return a; return gcd(b, a % b); } ll lcm(ll a, ll b) { //最小公倍数 return a * b / gcd(a, b); } int keta(ll n) { //桁数を求める if(n == 0) return 1; int count = 0; while(n != 0) { n /= 10; count++; } return count; } ll ketasum(ll n) { //各桁の和 ll sum = 0; while(n != 0) { sum += n % 10; n /= 10; } return sum; } bool isprime(int n) { //素数判定 if(n==1)return false; if(n==2)return true; for(int i = 2;i<=sqrt(n);i++) { if(n%i==0) return false; } return true; } /* ----------------------end----------------------- */ #pragma endregion signed main() { int n;cin >> n; int ans = n; rep(i, 99) { int a; a=ketasum(ans); ans=a; } cout << ans << endl; return 0; }