#include <bits/stdc++.h>
using namespace std;
const int inf = 1012345678;
int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  int N, Q;
  cin >> N >> Q;
  vector<vector<int> > g(N);
  int limit = 0;
  for (int i = 0; i < N; ++i) {
    int x, rad = 1;
    cin >> x;
    for (int j = 2; j * j <= x; ++j) {
      int cnt = 0;
      while (x % j == 0) x /= j, cnt ^= 1;
      if (cnt == 1) g[i].push_back(j), rad *= j;
    }
    if (x > 1) g[i].push_back(x), rad *= x;
    limit = max(limit, rad);
  }
  vector<vector<pair<int, int> > > qs(N + 1);
  for (int i = 0; i < Q; ++i) {
    int L, R;
    cin >> L >> R;
    --L;
    qs[R].push_back(make_pair(L, i));
  }
  vector<vector<int> > curopt(limit + 1, vector<int>(8, -inf));
  vector<int> curbound(15, -inf);
  vector<int> ans(Q);
  for (int i = 0; i < N; ++i) {
    for (int j = 0; j < 1 << g[i].size(); ++j) {
      int rem = 0, mul = 1;
      for (int k = 0; k < g[i].size(); ++k) {
        if ((j >> k) & 1)
          mul *= g[i][k];
        else
          ++rem;
      }
      for (int k = 0; k <= 7; ++k) {
        curbound[rem + k] = max(curbound[rem + k], curopt[mul][k]);
      }
      curopt[mul][rem] = i;
    }
    for (pair<int, int> j : qs[i + 1]) {
      for (int k = 0; k <= 14; ++k) {
        if (curbound[k] >= j.first) {
          ans[j.second] = k;
          break;
        }
      }
    }
  }
  for (int i = 0; i < Q; ++i) {
    cout << ans[i] << '\n';
  }
  return 0;
}
