import sys
input = sys.stdin.buffer.readline

def main():
    N = int(input()); INF = pow(10,18)
    P = list(map(int,input().split()))
    L = [-1]*N
    for i,p in enumerate(P):
        L[p-1] = i+1
    #print(L)
    plus = 0
    minus = 0
    ans = 0
    for i in range(N-1):
        plus += L[i]
        minus = L[i+1]
        ans = max(ans, plus - minus)
    print(ans)        

if __name__ == '__main__':
    main()