#include <cstdio>
#include <iostream>
#include <algorithm>
using namespace std;

long long k, n, m;
long long a[200100];
long long t[200100];
long long sum[200100];
int main () {
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    sum[i + 1] = sum[i] + a[i];
  }
  long long sz = 0, prev = 0;
  for (int i = 1; i <= m; i++) {
    cin >> t[i];
    sz += t[i] - t[i - 1] - 1 - sz;
    if (sz >= n) {
      cout << n - prev + t[i - 1];
      return 0;
    }
    long long low = 0, high = sz, mid;
    while (low < high) {
      mid = low + (high - low) / 2;
      int val = sum[sz] - sum[sz - mid];
      if (val > k)
        high = mid;
      else low = mid + 1;
    }
    sz -= high;
    prev = sz;
  }
  cout << n - sz + t[m];
}
/*
5 1 4
1
2
3
4
5
4

5 3 6
1
2
3
4
5
4 5 6
*/