import heapq

def main():
    n = int(input())
    s, t = map(int, input().split())
    a = list(map(int, input().split()))
    used = [False] * (n + 1)  # 1-based indexing

    # Mark initial positions as used
    used[s] = True
    used[t] = True

    x = a[s-1]
    y = a[t-1]

    heap315 = []
    heap8128 = []

    def get_neighbors(u):
        if u == 1:
            return [2, n]
        elif u == n:
            return [1, n-1]
        else:
            return [u-1, u+1]

    # Initialize heaps for both players
    for neighbor in get_neighbors(s):
        if not used[neighbor]:
            heapq.heappush(heap315, (-a[neighbor-1], neighbor))

    for neighbor in get_neighbors(t):
        if not used[neighbor]:
            heapq.heappush(heap8128, (-a[neighbor-1], neighbor))

    turn = 0  # 0 for 315's turn, 1 for 8128's turn

    while heap315 or heap8128:
        if turn == 0:
            # 315's turn
            while heap315:
                current_a, u = heapq.heappop(heap315)
                current_a = -current_a
                if not used[u]:
                    x += current_a
                    used[u] = True
                    for v in get_neighbors(u):
                        if not used[v]:
                            heapq.heappush(heap315, (-a[v-1], v))
                    break
            turn = 1
        else:
            # 8128's turn
            while heap8128:
                current_a, u = heapq.heappop(heap8128)
                current_a = -current_a
                if not used[u]:
                    y += current_a
                    used[u] = True
                    for v in get_neighbors(u):
                        if not used[v]:
                            heapq.heappush(heap8128, (-a[v-1], v))
                    break
            turn = 0

    print(x - y)

if __name__ == "__main__":
    main()