#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

constexpr int pow5(int e) {
  int res = 1;
  rep(_, e) res *= 5;
  return res;
}

template<int e>
void solve(int n) {
  if (e == 0) {
    cout << 0 << '\n';
    return;
  }
  constexpr int mod = pow5(e);
  using mint = static_modint<mod>;
  constexpr int mx = min(1 << 29, (mod + 1) / 2);
  mint tgt = n;
  for(int i = 0; i <= mx; i++) {
    mint r = mint::raw(i);
    mint r2 = r * r;
    if (r2 == tgt) {
      cout << r.val() << '\n';
      return;
    }
  }
  cout << "NaN\n";
}

template<int e>
void select_solver(int n, int e_in) {
  if (e_in == e) solve<e>(n);
  else select_solver<e-1>(n, e_in);
}

template<>
void select_solver<-1>(int, int) {
  assert(false);
}

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, e;
  cin >> n >> e;
  select_solver<13>(n, e);
  cout << flush;
}