#include namespace { #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wunused-function" #include #pragma GCC diagnostic pop using namespace std; using namespace atcoder; #define rep(i,n) for(int i = 0; i < (int)(n); i++) #define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--) #define all(x) begin(x), end(x) #define rall(x) rbegin(x), rend(x) template bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; } template bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; } using ll = long long; using P = pair; using VI = vector; using VVI = vector; using VL = vector; using VVL = vector; } int main() { ios::sync_with_stdio(false); cin.tie(0); int n; ll m; cin >> n >> m; map mp; bool half = false; int ans = 0; rep(_, n) { ll x; cin >> x; x %= m; if (x + x == m) { ans += !half; half = true; } else { if (x < m - x) mp[x].first++; else mp[m - x].second++; } } for(auto [_, v]: mp) ans += max(v.first, v.second); cout << ans << '\n'; }