//#include"holiday.h"
#include <bits/stdc++.h>
#define ll long long
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define MP make_pair
#define fs first
#define se second
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define pb push_back
#define SZ(v) (ll)v.size()
#define ALL(v) v.begin(),v.end()
using namespace std;
mt19937_64 rd(chrono :: steady_clock :: now ().time_since_epoch().count());
ll Rand (ll l, ll r) { return uniform_int_distribution<ll> (l, r) (rd); }
const int N = 3e5 + 7;
int Mod = 998244353;///lon
const ll INF = 1e18;
const ll BASE = 137;
const int szBL = 450;
inline void minimize (int &A, int B) {
if (A > B) A = B;
}
int n, K;
int a[N], b[N], c[N];
pii spt[N][25];
int lg[N];
namespace sub3 {
const int N3 = 400 + 7;
int dp[2][N3 * N3], pre[N3 * N3], suf[N3 * N3];
void solution () {
int bound = min((K + 1) * n, 400 * 400);
rep (j, 0, bound) dp[0][j] = j;
rep (i, 0, n - 1) {
rep (j, 0, bound) {
dp[i & 1 ^ 1][j] = 2e9;
}
pre[0] = dp[i & 1][0], suf[bound + 1] = 2e9;
rep (j, 1, bound) pre[j] = min(pre[j - 1], dp[i & 1][j] - j);
reb (j, bound, 0) suf[j] = min(suf[j + 1], dp[i & 1][j]);
rep (j, 0, bound) {
if ((a[i + 1] + j) % (K + 1) != b[i + 1]) continue;
dp[i & 1 ^ 1][j] = min(pre[j] + j, suf[j + 1]);
// cout << i + 1 <<" "<<j<<" "<<dp[i & 1 ^ 1][j] <<"\n";
}
}
int res = 2e9;
rep (j, 0, K) res = min(res, dp[n & 1][j]);
cout << res <<"\n";
}
}
namespace sub2 {
void solution() {
int res = 0;
rep (i, 1, n) {
if (c[i] != c[i - 1] && c[i] == 1) ++res;
}
cout << res <<"\n";
}
}
void solution () {
cin >> n >> K;
rep (i, 1, n) {
cin >> a[i];
}
rep (i, 1, n) {
cin >> b[i];
}
rep (i, 1, n) {
c[i] = ((b[i] - a[i]) % (K + 1) + K + 1) % (K + 1);
}
if (K <= 1)
sub2 :: solution();
else if (n <= 400)
sub3 :: solution();
else {
rep (i, 1, n) {
spt[i][0] = MP(c[i], i);
lg[i] = log2(i);
}
for (int j = 1; (1 << j) <= n; ++j)
for (int i = 1; i + (1 << j) - 1 <= n; ++i) {
spt[i][j] = min(spt[i][j - 1], spt[i + (1 << j - 1)][j - 1]);
}
auto get_Min = [] (int L, int R) {
int K = lg[R - L + 1];
return min(spt[L][K], spt[R - (1 << K) + 1][K]);
};
ll res = 0;
function<void(int, int, int)> dnc = [&] (int L, int R, int Delta) {
if (L > R) return 0;
int Mn, pos;
tie(Mn, pos) = get_Min(L, R);
res += Mn - Delta;
dnc(L, pos - 1, Mn);
dnc(pos + 1, R, Mn);
};
dnc(1, n, 0);
cout << res <<"\n";
}
}
#define file(name) freopen(name".inp","r",stdin); \
freopen(name".out","w",stdout);
int main () {
file("CODE");
ios_base :: sync_with_stdio(false); cin.tie(0); cout.tie(0);
int num_Test = 1;
// cin >> num_Test;
while (num_Test--)
solution();
}
/*
no bug challenge +10
5 5
01101
10001
00110
10101
00100
*/
