N = int(input())
A = [0]+list(map(int,input().split()))
indA = [0]*(N+1)
flagA = [0]*(N+1)
for i in range(1,N+1):
    indA[A[i]] = i
cnt = 0
for k in range(1,N+1):
    ind = indA[k]
    if flagA[ind]==0:
        cnt += 1
        flagA[ind] = 1
        if ind>1:
            flagA[ind-1] = 1
print(cnt)