#include <stdio.h>
#include <algorithm>
#include <assert.h>
#include <set>
#include <map>
#include <complex>
#include <iostream>
#include <time.h>
#include <stack>
#include <stdlib.h>
#include <memory.h>
#include <bitset>
#include <math.h>
#include <string>
#include <string.h>
#include <queue>
#include <vector>

using namespace std;

const int MaxN = 3.2e7 + 10;
const int MOD = 1e9 + 7;
const int INF = 1e9;

int lp[MaxN], pr[MaxN / 10], sz;

bool prime(long long x) {
  if (x < MaxN) {
    return lp[x] == x;
  }
  for (int i = 0; i < sz && 1LL * pr[i] * pr[i] <= x; ++i) {
    if (x % pr[i] == 0) {
      return false;
    }
  }
  return true;
}

int main() {
//  freopen("input.txt", "r", stdin);
  for (int i = 2; i < MaxN; ++i) {
    if (!lp[i]) {
      lp[i] = pr[sz++] = i;
    }
    for (int j = 0; j < sz && i * pr[j] < MaxN && pr[j] <= lp[i]; ++j) {
      lp[i * pr[j]] = pr[j];
    }
  }
  long long a, b;
  cin >> a >> b;
  if (prime(b - a)) {
    cout << a << "->" << b << '\n';
    exit(0);
  }
  if (a == 3 && b == 7) {
    cout << a << "->" << a + 2 << "->" << b << '\n';
    exit(0);
  }
  if (a == 2) {
    if (prime(b + 2)) {
      cout << a << "->" << b + 2 << "->" << b << '\n';
      exit(0);
    }
  }
  if (prime(a - 2)) {
    if (prime(b - 2)) {
      cout << a << "->" << 2 << "->" << b << '\n';
      exit(0);
    }
    if (prime(b + 2)) {
      cout << a << "->" << 2 << "->" << b + 2 << "->" << b << '\n';
      exit(0);
    }
  }
  if (prime(a + 2)) {
    if (prime(b - 2)) {
      cout << a << "->" << a + 2 << "->" << 2 << "->" << b << '\n';
      exit(0);
    }
    if (prime(b + 2)) {
      cout << a << "->" << a + 2 << "->" << 2 << "->" << b + 2 << "->" << b << "\n";
      exit(0);
    }
  }
  cout << "Unlucky Benny\n";
  return 0;
}