#include <bits/stdc++.h>
#define int long long
using namespace std;

constexpr int N = 100010;
int n, k, p, a[N], b[N], ans, z;

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	freopen("defeat.in", "r", stdin);
	freopen("defeat.out", "w", stdout);
	cin >> n >> k >> p;
	for (int i = 1; i <= n; i++) cin >> a[i];
	for (int i = 1; i <= n; i++) {
		a[i] += z;
		if (a[i] < k) {
			ans += k - a[i];
			z += k - a[i];
		} else if (a[i] > k) {
			ans += a[i] - k;
			z -= a[i] - k;
		}
	}
	cout << ans;
	return 0;
}