#include <bits/stdc++.h>

#include <atcoder/modint>

using namespace std;

using atcoder::modint;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int N, E;
  cin >> N >> E;

  int mod = 1;
  modint ::set_mod(mod);
  modint ans = 0;
  while (E--) {
    modint::set_mod(mod * 5);
    int r = ans.val();
    bool found = false;
    for (int i = 0; i < 5; ++i) {
      auto x = modint(r + i * mod);
      if (x * x == N) {
        ans = x;
        found = true;
        break;
      }
    }
    if (!found) {
      cout << "NaN\n";
      return 0;
    }
    mod *= 5;
  }
  int ans2 = min(ans.val(), (-ans).val());
  if (1 << 29 < ans2) {
    ans2 -= mod;
    if (ans2 < -(1 << 29)) {
      cout << "NaN\n";
      return 0;
    }
  }
  cout << ans2 << '\n';
}