func_code_string: #include <bits/stdc++.h>   using namespace std;   const int Maxn = 2e6 + 14;   int n, a[Maxn], b[Maxn], ans, m;   int main() {     cin >> n;     for (int i = 0; i < n; i++) cin >> a[i], b[a[i]] = a[i], m = max(m, a[i]);     sort(a, a + n);     for (int i = 1; i <= 2 * m; i++) {       if (b[i] == 0) b[i] = b[i - 1];     }     for (int i = m - 1; i > ans; i--) {       if (b[i] == i)         for (int j = i * 2 - 1; j < 2 * m; j += i) {           ans = max(ans, b[j] % i);         }     }     cout << ans;   }   