#include <iostream> #include <numeric> #include <cmath> #include <limits> #include <stdio.h> #include <iomanip> #include <string> // string, to_string, stoi #include <vector> // vector #include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound #include <utility> // pair, make_pair #include <tuple> // tuple, make_tuple #include <cstdint> // int64_t, int*_t #include <cstdio> // printf #include <map> // map #include <queue> // queue, priority_queue #include <set> // set #include <stack> // stack #include <deque> // deque #include <unordered_map> // unordered_map #include <unordered_set> // unordered_set #include <bitset> // bitset #include <cctype> // isupper, islower, isdigit, toupper, tolower using namespace std; using ll = long long; #define rep(i, n) for (long long i = 0; i < (long long)(n); i++) ll Max(ll(a), ll(b), ll(c)) { return max(max(a, b), c); } ll Min(ll(a), ll(b), ll(c)) { return min(min(a, b), c); } ll keta(ll n) { ll k = n; ll an = 0; while (k > 0) { k /= 10; an++; } return an; } ll ketawa(ll n) { ll k = n; ll an = 0; while (k > 0) { an += k % 10; k /= 10; } return an; } int main() { ll N; cin >> N; rep(i, 99) { N = ketawa(N); } cout<< N << endl; }