1 //#pragma comment(linker, "/STACK:167772160")//手动扩栈~~~~hdu 用c++交
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <iostream>
 6 #include <queue>
 7 #include <stack>
 8 #include <cmath>
 9 #include <set>
10 #include <algorithm>
11 #include <vector>
12 #include <map>
13 // #include<malloc.h>
14 using namespace std;
15 #define clc(a,b) memset(a,b,sizeof(a))
16 #define LL long long
17 const int inf = 0x3f3f3f3f;
18 const double eps = 1e-5;
19 // const double pi = acos(-1);
20 const LL MOD = 9901;
21 const int N = 110;
22
23 // inline int r(){
24 //     int x=0,f=1;char ch=getchar();
25 //     while(ch>'9'||ch<'0'){if(ch=='-') f=-1;ch=getchar();}
26 //     while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
27 //     return x*f;
28 // }
29 char a[N],b[N];
30 int dp[N][N];
31 int ans[N];
32
33 int main(){
34     while(~scanf("%s%s",a,b)){
35         int n=strlen(a);
36         clc(dp,0);
37         for(int i=0;i<n;i++){
38             for(int j=i;j<n;j++){
39                 dp[i][j]=j-i+1;
40             }
41         }
42
43         for(int len=0;len<n;len++){
44             for(int i=0;i<n&&i+len<n;i++){
45                 int j=i+len;
46                 dp[i][j]=dp[i+1][j]+1;
47                 for(int k=i+1;k<=j;k++){
48                     if(b[i]==b[k])
49                     dp[i][j]=min(dp[i][j],dp[i+1][k]+dp[k+1][j]);
50                 }
51             }
52         }
53
54         if(a[0]==b[0]) {
55             ans[0]=0;
56         }
57         else
58             ans[0]=1;
59         for(int i=1;i<n;i++){
60             ans[i]=dp[0][i];
61             if(a[i]==b[i]){
62                 ans[i]=ans[i-1];
63             }
64             else{
65                 for(int k=0;k<i;k++){
66                     ans[i]=min(ans[i],ans[k]+dp[k+1][i]);
67                 }
68             }
69         }
70         printf("%d\n",ans[n-1]);
71     }
72     return 0;
73 }