# boj.kr/15483
from sys import stdin
READ = lambda : stdin.readline().strip()

a = READ()
b = READ()
n, m = len(a), len(b)
dp = [[0] * (m + 1) for _ in range(n + 1)]

for i in range(1, n+1):
    dp[i][0] = i
for j in range(1, m+1):
    dp[0][j] = j

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

print(dp[n][m])