#include #include #include using namespace std; long long int n; string cur; void MOD(){ reverse(cur.begin(), cur.end()); while (cur.size() > 12){ cur.pop_back(); } reverse(cur.begin(), cur.end()); } bool check(){ for (int i = 0; i < cur.size(); i++){ if (cur[i] == '0'){ } else{ return false; } } return true; } string pluss(string a, string b, bool flag = false){ if (!flag){ reverse(a.begin(), a.end()); reverse(b.begin(), b.end()); } if (a.size() > b.size()){ swap(a, b); } string ans; ans.clear(); long long int want = 0; for (int i = 0; i < a.size(); i++){ long long int val = a[i] - '0'; val += b[i] - '0'; val += want; want = val / 10LL; val %= 10LL; ans.push_back(val + '0'); } for (int j = a.size(); j < b.size(); j++){ long long int val = 0; val += b[j] - '0'; val += want; want = val / 10LL; val %= 10LL; ans.push_back(val + '0'); } while (want){ ans.push_back(want % 10 + '0'); want /= 10; } if (!flag){ reverse(ans.begin(), ans.end()); } if (ans.size() == 0)ans = "0"; return ans; } string mult(string a, string b, bool flag = false){ if (!flag){ reverse(a.begin(), a.end()); reverse(b.begin(), b.end()); } string ans = "0"; string pas; string kari; pas.clear(); for (int i = 0; i < b.size(); i++){ long long int bb = b[i] - '0'; long long int tmp = 0; kari = pas; for (int j = 0; j < a.size(); j++){ long long int val = (long long int)(a[j] - '0')*bb; val += tmp; tmp = val / 10LL; val %= 10LL; kari.push_back(val + '0'); } while (tmp){ kari.push_back((tmp % 10LL) + '0'); tmp /= 10LL; } ans = pluss(ans, kari, true); //end pas.push_back('0'); } if (!flag){ reverse(ans.begin(), ans.end()); } if (ans.size() == 0)ans = "0"; return ans; } string minuss(string a, string b){ reverse(b.begin(), b.end()); reverse(a.begin(), a.end()); while (a.size()>b.size()){ b.push_back('0'); } while (a.size()= b[i]){ a[i] = (a[i] - '0') - (b[i] - '0') + '0'; } else{ a[i] = (10 + (a[i] - '0') - (b[i] - '0')) + '0'; carry = true; } } while (a.size()>1 && a.back() == '0'){ a.pop_back(); } reverse(a.begin(), a.end()); return a; } int main(){ scanf("%lld", &n); cur = "1"; for (long long int i = 2; i <= n; i++){ stringstream ss; ss << i; string k; ss >> k; cur = mult(cur, k); MOD(); if (check()){ break; } } MOD(); cout << cur << endl; return 0; }