func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 5e5 + 5;   int n = 5e5, f[N], s[N];   vector<int> v[N];   int q, a[N], c[N];   int main() {     int i, j, t;     long long ans;     for (i = 1; i <= n; i = i + 1) {       if (i == 1) f[i] = 1;       for (j = i; j <= n; j = j + i) {         v[j].push_back(i);         if (j > i) f[j] -= f[i];       }     }     scanf( %d%d , &n, &q);     for (i = 1; i <= n; i = i + 1) scanf( %d , a + i);     ans = 0;     while (q--) {       scanf( %d , &i);       t = v[a[i]].size();       if (c[i]) {         c[i] = 0;         i = a[i];         for (j = 0; j < t; j = j + 1) ans -= f[v[i][j]] * (--s[v[i][j]]);       } else {         c[i] = 1;         i = a[i];         for (j = 0; j < t; j = j + 1) ans += f[v[i][j]] * (s[v[i][j]]++);       }       cout << ans << endl;     }     return 0;   }   