def find_LIS_length(sequence):
    from bisect import bisect_left
    LIS = []
    for value in sequence:
        pos = bisect_left(LIS, value)
        if pos == len(LIS):
            LIS.append(value)
        else:
            LIS[pos] = value
    return len(LIS)

def minimum_operations_to_strictly_increasing(N, ratings):
    # ratingsは1からNまでの順列であるため、直接LISを求める
    return N - find_LIS_length(ratings)

# 入力
N = int(input())
ratings = list(map(int, input().split()))

# 出力
print(minimum_operations_to_strictly_increasing(N, ratings))