#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
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<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  ll k;
  cin >> n >> k >> m;
  VI b(n), c(n);
  rep(i, n) cin >> b[i];
  rep(i, n) cin >> c[i];
  VL d(n + 1);
  rep(i, n) d[i+1] = d[i] + b[i];
  vector<pair<ll, int>> evs;
  rep(i, n + 1) {
    int pre = i == 0 ? 0 : c[i-1];
    int nxt = i == n ? 0 : c[i];
    evs.emplace_back(d[i], nxt - pre);
    if (d[i] + k <= d[n]) evs.emplace_back(d[i] + k, -(nxt - pre));
  }
  evs.emplace_back(d[n] + 1, 0);
  sort(all(evs));
  ll t_pre = 0;
  int val = 0, inc = 0;
  ll ans = 0;
  for (auto [t_nxt, add] : evs) {
    if (t_pre >= k) {
      auto [g, inv] = internal::inv_gcd(inc, m);
      ll d = t_nxt - t_pre;
      if (val % g == 0) {
        int r = (m - val) / g * inv % m;
        int p = m / g;
        if (r < d) ans += (d - r + p - 1) / p;
      }
    }
    val = (val + inc * (t_nxt - t_pre)) % m;
    if (val < 0) val += m;
    inc += add;
    t_pre = t_nxt;
  }
  cout << ans << '\n';
}