N, M = map(int, input().split()) A = list(map(int, input().split())) B = list(map(int, input().split())) def f(data): res = [] for a in data: res.append(0) res += [1] * a return res A = f(A) B = f(B) N = len(A) M = len(B) INF = 10**18 dp = [[INF]*(M+1) for _ in range(N+1)] dp[0][0] = 0 for i, ai in enumerate(A, start=1): for j, bj in enumerate(B, start=1): cost = int(ai != bj) dp[i][j] = min( dp[i][j], dp[i-1][j-1]+cost, dp[i][j-1]+1, dp[i-1][j]+1 ) print(dp[-1][-1])