#include <array>
#include <cstdio>
#include <unistd.h>

constexpr auto max_n = 100000;

constexpr auto create_buf() {
  std::array<char, 2 + max_n> buf { "0." };
  for (std::size_t i = 2; i < 2 + max_n; ++i) {
    buf[i] = "142857"[(i - 2) % 6];
  }
  return buf;
}

int main() {
  constexpr auto buf = create_buf();
  std::size_t n;
  scanf("%zu", &n);
  write(STDOUT_FILENO, buf.data(), n == 0 ? 1 : n + 2);
}