def levenshtein_distance(s1, s2):
    n1, n2 = len(s1), len(s2)
    dp = [[float("inf")]*(n2+1) for _ in range(n1+1)]
    for i in range(n1 + 1):
        dp[i][0] = i
    for j in range(n2 + 1):
        dp[0][j] = j
    for i in range(n1):
        for j in range(n2):
            # 変更操作
            if s1[i] == s2[j]:
                dp[i + 1][j + 1] = min(dp[i + 1][j + 1], dp[i][j])
            else:
                dp[i + 1][j + 1] = min(dp[i + 1][j + 1], dp[i][j] + 1)
            # 削除操作
            dp[i + 1][j + 1] = min(dp[i + 1][j + 1], dp[i][j + 1] + 1)
            # 挿入操作
            dp[i + 1][j + 1] = min(dp[i + 1][j + 1], dp[i + 1][j] + 1)

    return (dp[n1][n2], dp)

def solve():
    s1 = input()
    s2 = input()
    opnum, dp = (levenshtein_distance(s1, s2))
    print(opnum)

N,M=map(int,input().split())
solve()