from sys import stdin


def main():
    input = lambda: stdin.readline()[:-1]
    N = int(input())
    P = map(int, input().split())

    if N == 1:
        print(0)
        return

    take, suzu = 0, 0
    for i, p in enumerate(P, start=1):
        if p < N:
            take += i
        else:
            suzu += i
    print(take - suzu)


main()