Problem: Janusz is a businessman. He owns a company "Januszex", which produces games for teenagers. Last hit of Januszex was a cool one-person game "Make it one". The player is given a sequence of n integers a_i.

It is allowed to select any subset of them, and the score is equal to the greatest common divisor of selected elements. The goal is to take as little elements as it is possible, getting the score 1. Now Janusz wonders, for given sequence, how much elements should the player choose?

Input

The first line contains an only integer n (1 ≤ n ≤ 300 000) — the number of integers in the sequence.

The second line contains n integers a_1, a_2, …, a_n (1 ≤ a_i ≤ 300 000).

Output

If there is no subset of the given sequence with gcd equal to 1, output -1.

Otherwise, output exactly one integer — the size of the smallest subset with gcd equal to 1.

Examples

Input

3
10 6 15


Output

3


Input

3
2 4 6


Output

-1


Input

7
30 60 21 42 70 15 30


Output

3

Note

In the first example, selecting a subset of all numbers gives a gcd of 1 and for all smaller subsets the gcd is greater than 1.

In the second example, for all subsets of numbers the gcd is at least 2. 

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 5;
const int Mod = 1e9 + 7;
namespace pb_ds {
namespace io {
const int MaxBuff = 1 << 15;
const int Output = 1 << 23;
char B[MaxBuff], *S = B, *T = B;
char Out[Output], *iter = Out;
inline void flush() {
  fwrite(Out, 1, iter - Out, stdout);
  iter = Out;
}
}  // namespace io
template <class Type>
inline Type Read() {
  using namespace io;
  register char ch;
  register Type ans = 0;
  register bool neg = 0;
  while (ch = ((S == T) && (T = (S = B) + fread(B, 1, MaxBuff, stdin), S == T)
                   ? 0
                   : *S++),
         (ch < '0' || ch > '9') && ch != '-')
    ;
  ch == '-' ? neg = 1 : ans = ch - '0';
  while (ch = ((S == T) && (T = (S = B) + fread(B, 1, MaxBuff, stdin), S == T)
                   ? 0
                   : *S++),
         '0' <= ch && ch <= '9')
    ans = ans * 10 + ch - '0';
  return neg ? -ans : ans;
}
template <class Type>
inline void Print(register Type x, register char ch = '\n') {
  using namespace io;
  if (!x)
    *iter++ = '0';
  else {
    if (x < 0) *iter++ = '-', x = -x;
    static int s[100];
    register int t = 0;
    while (x) s[++t] = x % 10, x /= 10;
    while (t) *iter++ = '0' + s[t--];
  }
  *iter++ = ch;
}
}  // namespace pb_ds
using namespace pb_ds;
int n, mx, a[N], dp[20][N];
int fac[N], cnt[N], inv[N];
inline int Pow(int x, int y) {
  int res = 1;
  while (y) {
    if (y & 1) res = 1ll * res * x % Mod;
    x = 1ll * x * x % Mod;
    y >>= 1;
  }
  return res;
}
int gcd(int x, int y) {
  if (!y) return x;
  return gcd(y, x % y);
}
inline void init() {
  fac[0] = 1;
  for (int i = 1; i <= N - 5; ++i) fac[i] = 1ll * fac[i - 1] * i % Mod;
  inv[N - 5] = Pow(fac[N - 5], Mod - 2);
  for (int i = N - 5; i; --i) inv[i - 1] = 1ll * inv[i] * i % Mod;
}
inline int C(int x, int y) {
  if (x < y || y < 0) return 0;
  return (1ll * (1ll * fac[x] * inv[y] % Mod) * inv[x - y] % Mod);
}
int main() {
  n = Read<int>();
  init();
  int k = 0;
  for (int i = 1; i <= n; ++i) {
    ++cnt[a[i] = Read<int>()];
    k = gcd(k, a[i]);
    mx = max(a[i], mx);
  }
  if (k != 1) {
    printf("-1\n");
    return 0;
  }
  for (int i = 1; i <= 300000; ++i)
    for (int j = i + i; j <= 300000; j += i) cnt[i] += cnt[j];
  int now = 0;
  for (int i = 1; i < 20; ++i) {
    for (int j = 300000; j; --j) {
      dp[i][j] = C(cnt[j], i);
      for (int k = j + j; k <= 300000; k += j) {
        dp[i][j] -= dp[i][k];
        if (dp[i][j] < 0) dp[i][j] += Mod;
      }
    }
    if (dp[i][1] > 0) {
      printf("%d\n", i);
      return 0;
    }
  }
  return 0;
}