a = list(input())
b = list(input())
dp = [[0] * (len(a)+1) for x in range(len(b)+1)]
for i in range(len(b)+1):
    dp[i][0] = i
for j in range(len(a)+1):
    dp[0][j] = j

for i in range(1, len(b)+1):
        for j in range(1, len(a)+1):
            dp[i][j] = min(dp[i-1][j], dp[i][j-1]) + 1
            dp[i][j] = min(dp[i][j], dp[i-1][j-1] + (a[j-1] != b[i-1]))
            if b[i-1] == a[j-1]:
                dp[i][j] = dp[i-1][j-1]

print(dp[-1][-1])