#include <stdlib.h>
#include <stdio.h>
#include <string.h>

struct queue
{
    int Pi;
    struct queue *next;
    struct queue *prev;
    int pos;
};

/**
 * \breif Add an element to the queue
 * \param q The queue to add the element
 * \param Pi The data of the element
 * \param i The index of the element
 * \return The queue with the new element
 */
struct queue *add_elt(struct queue *q, int Pi, int i)
{
    struct queue *n = malloc(sizeof(*n));
    if (!n)
        return NULL;
    n->Pi = Pi;
    n->next = NULL;
    n->prev = q;
    n->pos = i;
    if (q)
        q->next = n;
    return n;
}

/**
 * \breif Free the memory of the queue
 * \param q The queue to freed
 * \param N The size of the queue
 */
void free_queue(struct queue *q, int N)
{
    struct queue *tmp = q;
    while (tmp->pos != N - 1)
        tmp = tmp->next;
    tmp->next = NULL;
    while (q)
    {
        tmp = q;
        q = q->next;
        free(tmp);

    }
}

/**
 * \breif Check if a number is already in an array
 * \param t The array to check
 * \param pos the number to check
 * \param size The size of the array
 * \return Returns 0 if the number is not present and the position of the number if it is
 */
int check_pos(int t[], int pos, int size)
{
    for (int i = 0; i < size; i++)
        if (pos == t[i])
            return i;
    return 0;
}

/**
 * \brief Function that fill the carousel
 * \param q struct queue that contains the number of people per group
 * \param L The max capacity of the carousel
 * \param N The max capacity of the queue
 * \param res A pointer on the total earnings
 * \return struct *queue Return the queue to keep the head at the good place
 */
struct queue *fill(struct queue *q, int L, int N, long *res)
{
    int max = L;
    for (;N > 0 && (L - q->Pi) >= 0; N--)
    {
        L -= q->Pi;
        q = q->next;
    }
    *res += max - L;
    return q;
}

/**
 * \brief Function that computes the gains
 * \param q struct queue that contains the number of people per group
 * \param C The number of cycle possible
 * \param L The max capacity of the carousel
 * \param N The max capacity of the queue
 * \return Long, The sum of all the dirhams earned
 */
long turn(struct queue *q, int C, int L, int N)
{
    long res = 0;
    int m_C = C;
    int pos[N];
    long t_res[N];
    int cycle = 0;
    long dir = 0;
    for (; C > 0; C--)
    {
        int i = check_pos(pos, q->pos, m_C - C);
        if (!i)
        {
            pos[m_C - C] = q->pos;
            t_res[m_C - C] = res;
        }
        else
        {
            dir = res - t_res[i];
            cycle = m_C - (C + i);
            break;
        }
        q = fill(q, L, N, &res);
    }
    if (dir)
    {
        int mult = C / cycle;
        int mod_C = C % cycle;
        res += mult * dir;
        for(; mod_C > 0; mod_C--)
            q = fill(q, L, N, &res);
    }
    return res;
}

int main()
{
    int L;
    int C;
    int N;
    scanf("%d%d%d", &L, &C, &N);
    struct queue *q = NULL;
    for (int i = 0; i < N; i++) {
        int Pi;
        scanf("%d", &Pi);
        q = add_elt(q, Pi, i);
    }
    struct queue *tmp = q;
    while (tmp->prev)
        tmp = tmp->prev;
    q->next = tmp;
    q = tmp;

    long res = turn(q, C, L, N);
    printf("%ld\n", res);
    free_queue(q, N);
    return 0;
}