#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define int long long #define ii pair #define app push_back #define all(a) a.begin(), a.end() #define bp __builtin_popcountll #define ll long long #define mp make_pair #define x first #define y second #define Time (double)clock()/CLOCKS_PER_SEC #define munq(a) sort(all(a)); a.resize(unique(all(a))-a.begin()) #define sz(a) ((int)a.size()) #ifdef LOCAL #define debug(x) do { cout << #x << ": " << x << endl; } while(0) #define debug2(x, y) do { std::cerr << #x << ", " << #y << ": " << x << ", " << y << endl; } while (0) #define debug3(x, y, z) do {std::cerr << #x << ", " << #y << ", " << #z << ": " << x << ", " << y << ", " << z << endl; } while(0) #else #define debug(x) #define debug2(x, y) #define debug3(x, y, z) #endif #define FORI(i,a,b) for (int i = (a); i < (b); ++i) #define FOR(i,a) FORI(i,0,a) #define ROFI(i,a,b) for (int i = (b)-1; i >= (a); --i) #define ROF(i,a) ROFI(i,0,a) #define rep(a) FOR(_,a) #define each(a,x) for (auto& a: x) #define FORN(i, n) FORI(i, 1, n + 1) using vi = vector; template std::istream& operator >>(std::istream& input, std::pair & data) { input >> data.x >> data.y; return input; } template std::istream& operator >>(std::istream& input, std::vector& data) { for (T& x : data) input >> x; return input; } template std::ostream& operator <<(std::ostream& output, const pair & data) { output << "(" << data.x << "," << data.y << ")"; return output; } template std::ostream& operator <<(std::ostream& output, const std::vector& data) { for (const T& x : data) output << x << " "; return output; } ll div_up(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up ll div_down(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down ll math_mod(ll a, ll b) { return a - b * div_down(a, b); } #define tcT template using V = vector; tcT> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; } // set a = min(a,b) tcT> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } tcT> vector presum(vector &a) { vector p(a.size() + 1); FOR (i, a.size()) { p[i + 1] = p[i] + a[i]; } return p; } tcT> vector sufsum(vector &a) { vector p(a.size() + 1); for (int i = (int)a.size() - 1; i >= 0; --i) { p[i] = p[i + 1] + a[i]; } return p; } ll gcd(ll a, ll b) { while (b) { tie(a, b) = mp(b, a % b); } return a; } int Bit(int mask, int bit) { return (mask >> bit) & 1; } signed main() { #ifdef LOCAL #else #define endl '\n' ios_base::sync_with_stdio(0); cin.tie(0); #endif int n, m; cin >> n >> m; vi a(n), b(n);cin>>a>>b; n++; a.app(0); b.app(0); vi c, d; FOR (i, n) { c.app((a[(i + 1)%n] - a[i])); d.app(b[(i + 1)%n] - b[i]); } debug2(c,d); vi e; FOR (i, n) { e.app(((d[i] - c[i])%m+m)%m); } sort(all(e)); debug(e); int ans = 1e18; int tot = accumulate(all(e), 0ll); int L = 0; FOR (i, n) { L += e[i]; int R = m * (sz(e) - i - 1) - (tot - L); debug3(i, L, R); ckmin(ans, max(L,R)); } cout<