#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using ll=long long; #define int ll #define rng(i,a,b) for(int i=int(a);i=int(a);i--) #define per(i,b) gnr(i,0,b) #define eb emplace_back #define all(x) x.begin(),x.end() #define SZ(x) ((int)x.size()) #define fi first #define se second const int INF = 1e15; using namespace std; template using vc=vector; template using vvc=vc>; using pi=pair; using vi=vc; template inline bool chmax(T &a,T b){if(a inline bool chmin(T &a,T b){if(a>b){a=b;return true;}return false;} signed main() { cin.tie(0); ios::sync_with_stdio(0); cout<> N >> K; int A[N]; rep(i,N) cin >> A[i]; sort(A,A+N); reverse(A,A+N); int ans=0; rep(i,(1<>j)&1) pos%=A[j]; } chmax(ans,pos%A[N-1]); } cout << ans << endl; }