#include <cstdio>
#include <algorithm>

int n, k, p;
int a[100010];
long long ans;

int main() {
    freopen("defeat.in", "r", stdin);
    freopen("defeat.out", "w", stdout);
    scanf("%d %d %d", &n, &k, &p);
    for (int i = 1; i <= n; ++i) {
        scanf("%d", &a[i]);
    }
    
    if (p == 0) {
        int shift = 0;
        for (int i = 1; i <= n; ++i) {
            int realnum = a[i] + shift;
            int op = k - realnum;
            ans += abs(op);
            shift += op;
        }
        printf("%lld\n", ans);
    } else {
        printf("1\n");
    }
    return 0;
}