#include <iostream> using namespace std; // 计算小于等于 x 的美丽数的个数 int count_beautiful_numbers(int x) { return x / 3 + x / 5 - x / 15; } // 二分查找第 N 个美丽数 int find_nth_beautiful_number(int N) { int left = 1, right = 1000000; while (left < right) { int mid = (left + right) / 2; if (count_beautiful_numbers(mid) < N) { left = mid + 1; } else { right = mid; } } return left; } int main() { int N; while (cin >> N) { cout << find_nth_beautiful_number(N) << endl; } return 0; }