#include <bits/stdc++.h>   using namespace std;   const int N = 5e5 + 5;   int su[N], lst[N], n, i, a, lim;   long long ans;   pair<int, int> b[N];   int xb;   inline int calc(int k) {     int i, j;     long long s = 0, ans = -1, x, y, z;     xb = 0;     for (i = 0; i * k < N; ++i) {       s += 1ll * i * (su[min(N - 1, (i + 1) * k - 1)] - (i ? su[i * k - 1] : 0));       x = lst[min(N - 1, (i + 1) * k)];       if (x && x >= i * k) {         y = su[x] - su[x - 1] > 1 ? x : lst[x];         if (y >= i * k) b[++xb] = make_pair(i, y - i * k);         b[++xb] = make_pair(i, x - i * k);       }     }     for (i = 1; i <= xb; ++i) {       z = 2 * s - b[i].second;       x = z <= 0 ? 0 : (z - 1) / (k + 2) + 1;       if (x <= b[i].first) ans = max(ans, s - x);     }     y = -1;     if (k == 7) {       ++k, --k;     }     for (i = xb; i; --i) {       if (y >= 0) {         z = s - min(1ll * b[i].second, y);         x = z <= 0 ? 0 : (z - 1) / (k + 2) + 1;         if (x <= b[i].first) ans = max(ans, s - x * 2);       }       y = max(y, 1ll * b[i].second);     }     y = -1;     for (i = xb; i; --i) {       if (b[i].first < b[xb].first) {         z = s - 1 - b[i].second;         x = z <= 0 ? 0 : (z - 1) / (k + 2) + 1;         if (x <= b[i].first) ans = max(ans, s - x * 2 - 1);       }       if (y >= 0) {         z = s + 1 + k - y;         x = z <= 0 ? 0 : (z - 1) / (k + 2) + 1;         if (x <= b[i].first) ans = max(ans, s - x * 2 + 1);       }       y = max(y, 1ll * b[i].second);     }     return ans == -1 ? lim : (ans < 2 ? 0 : ans);   }   int main() {     scanf( %d , &n);     for (i = 0; i < n; ++i) scanf( %d , &a), ++su[a];     for (i = 1; i < N; ++i) lst[i] = su[i - 1] ? i - 1 : lst[i - 1];     a = lst[N - 1];     lim = max(a / 2, su[a] > 1 ? a : lst[a]);     for (i = 1; i < N; ++i) su[i] += su[i - 1];     for (i = 2; i < N; ++i) ans = max(ans, 1ll * i * calc(i));     printf( %lld n , ans);     return 0;   }   