include iostream include vector using namespace std int main int cin v

#include<iostream>
#include<vector>

using namespace std;

int main()
{
	int n, m, k;
	cin >> n >> m >> k;
	vector<int> num(n);
	vector< vector<int> > sum(n, vector<int>(n));
	for (int i = 0; i < n; ++i)
	{
		cin >> num[i];
		sum[0][i] = num[i];
		sum[i][0] = num[0];
	}

	for(int i = 1; i < n; ++i)
	for (int j = 1; j < n; ++j)
	{
		sum[i][j] = sum[i - 1][j - 1] + sum[0][j];
	}

	int t = n + m;
	int next = 0, bef = 0, step, now = 0;
	for (int i = 1; i <= m; ++i)
	{
		cin >> next;
		step = next - bef - 1;
		now += step;
		int l = 0;
		while (now > 0 && sum[l][now - 1] < k && l < n - 1)
			l++;
		if (now >= l + 1)
			now -= l + 1;
		else
		{
			l = now - 1;
			now = 0;
		}
		t += l + 1;
		bef = next;
	}
	cout << t << endl;
	return 0;	
}