#include <bits/stdc++.h>
using namespace std;
typedef long double LD;
const int N = 2 * 150000 + 5;
int n, m, c;
int x[N];
int q[N];
int p[N];
long long val[N];
int a[N], b[N];
int pr[N];
long long su[N];
long long mi[4 * N];
long long ma[4 * N];
long long ans[4 * N];
void build(int v, int tl, int tr) {
  if (tl == tr) {
    ma[v] = mi[v] = su[tl];
    ans[v] = 0;
    return;
  }
  int tm = (tl + tr) / 2;
  build(v + v, tl, tm);
  build(v + v + 1, tm + 1, tr);
  ans[v] = max(ans[v + v], ans[v + v + 1]);
  ma[v] = max(ma[v + v], ma[v + v + 1]);
  mi[v] = min(mi[v + v], mi[v + v + 1]);
  ans[v] = max(ans[v], ma[v + v + 1] - mi[v + v]);
}
void get(int v, int tl, int tr, int l, int r, long long &mi1, long long &ma1,
         long long &ans1) {
  if (l == tl && tr == r) {
    mi1 = mi[v];
    ma1 = ma[v];
    ans1 = ans[v];
    return;
  }
  int tm = (tl + tr) / 2;
  if (r <= tm) {
    get(v + v, tl, tm, l, r, mi1, ma1, ans1);
    return;
  }
  if (l > tm) {
    get(v + v + 1, tm + 1, tr, l, r, mi1, ma1, ans1);
    return;
  }
  long long mi2, ma2, ans2;
  get(v + v, tl, tm, l, tm, mi2, ma2, ans2);
  get(v + v + 1, tm + 1, tr, tm + 1, r, mi1, ma1, ans1);
  ans1 = max(ans1, ma1 - mi2);
  ans1 = max(ans1, ans2);
  ma1 = max(ma1, ma2);
  mi1 = min(mi1, mi2);
}
long long count_for(int s, int f) {
  long long ans, mi, ma;
  get(1, 1, n, s, f, mi, ma, ans);
  return ans;
}
void solve() {
  scanf("%d%d%d", &n, &m, &c);
  for (int i = 1; i <= (int)(n); ++i) scanf("%d", &x[i]);
  for (int i = 1; i <= (int)(n - 1); ++i) scanf("%d", &p[i]);
  for (int i = 1; i <= (int)(m); ++i) {
    scanf("%d%d", &a[i], &b[i]);
    ++q[a[i]];
    --q[b[i]];
  }
  long long cr = 0;
  for (int i = 1; i <= (int)(n); ++i) pr[i] = pr[i - 1] + p[i];
  for (int i = 1; i <= (int)(n - 1); ++i) {
    cr += q[i];
    val[i] = (long long)-2 * c * p[i];
    val[i] += (long long)(x[i + 1] - x[i]) * 100;
  }
  for (int i = 1; i <= (int)(n); ++i) su[i] = su[i - 1] + val[i - 1];
  build(1, 1, n);
  long long res = 0;
  for (int j = 1; j <= (int)(m); ++j) {
    res += count_for(a[j], b[j]);
  }
  cout << (LD)res / 200.0 << endl;
}
void testgen() {
  FILE *f = fopen("input.txt", "w");
  srand(time(0));
  fclose(f);
}
int main() {
  cout << fixed;
  cout.precision(23);
  solve();
  return 0;
}
