N = int(input())
P = list(map(int, input().split()))
P = P[::-1]
L = [0]*(N+1)
ans = 0
mi = 1
for i in range(N):
    p = P[i]
    for j in range(p+1,N+1):
        if L[j]==0:
            L[j]=1
            ans += N-i
            break
    else:
        if L[p]==0:
            L[p]=1
        else:
            for j in range(mi,N+1):
                if L[j]==0:
                    mi=j+1
                    L[j]=1

                    ans -= N-i
                    break
print(ans)