func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e6 + 5;   int par[N], ran[N];   struct DSU {     DSU() {       for (int i = 1; i < N; ++i) par[i] = i, ran[i] = 1;     }     int find(int x) { return par[x] == x ? x : par[x] = find(par[x]); }     bool unite(int a, int b) {       a = find(a), b = find(b);       if (a == b) return false;       ran[a] += ran[a] == ran[b];       if (ran[a] < ran[b]) swap(a, b);       par[b] = a;       return true;     }   };   int a[N];   int n, q;   vector<int> primes;   int spf[N];   void sieve() {     for (int i = 2; i < N; ++i) {       if (spf[i] == 0) spf[i] = i, primes.push_back(i);       int sz = primes.size();       for (int j = 0; j < sz && i * primes[j] < N && primes[j] <= spf[i]; ++j) {         spf[i * primes[j]] = primes[j];       }     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);     sieve();     cin >> n >> q;     DSU ds;     for (int i = 1; i <= n; ++i) {       cin >> a[i];     }     for (int i = 1; i <= n; ++i) {       int x = a[i];       while (x > 1) {         ds.unite(spf[a[i]], spf[x]);         x /= spf[x];       }     }     set<pair<int, int>> pary;     for (int i = 1; i <= n; ++i) {       int x = a[i];       vector<int> v;       while (x > 1) {         v.push_back(spf[x]);         x /= spf[x];       }       x = a[i] + 1;       while (x > 1) {         v.push_back(spf[x]);         x /= spf[x];       }       v.resize(unique(v.begin(), v.end()) - v.begin());       for (auto &j : v) {         j = ds.find(j);       }       for (auto j : v) {         for (auto k : v) {           if (j < k) pary.insert({j, k});         }       }     }     while (q--) {       int x, y;       cin >> x >> y;       x = spf[a[x]], y = spf[a[y]];       if (ds.find(x) == ds.find(y))         cout << 0 << endl;       else {         x = ds.find(x);         y = ds.find(y);         if (x > y) swap(x, y);         if (pary.count({x, y}))           cout << 1 << endl;         else           cout << 2 << endl;       }     }   }   