1 #include <bits/stdc++.h>
2 using namespace std;
3 typedef long long ll;
4 #define inf 0x7fffffff
5 #define faster ios::sync_with_stdio(0);cin.tie(0)
6
7 inline ll read()
8 {
9 int x=0,f=1;char ch=getchar();
10 while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
11 while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
12 return x*f;
13 }
14
15 /********************************************************************/
16
17 const int maxn = 1000000+7;
18 int n;
19 char s[2];
20 char ch[maxn];
21
22 int main(){
23 int t;
24 t = read();
25 while(t--){
26 n = read();
27 scanf("%s", s);
28 scanf("%s", ch);
29 int ans = 0;
30 int flag = 0; //是头
31 for(int i = 0;i < n;i++){
32 if(flag == 0){
33 int x = abs(s[0] - ch[i]);
34 //cout << "x : " << x << endl;
35 if(x == 0)
36 continue;
37 if(x < 10){
38 ans = 1;
39 }
40 else
41 ans = 2;
42 flag = 1;
43 continue;
44 }
45 else
46 ans += 2;
47 }
48 if(ans == 0)
49 ans = 1;
50 printf("%d\n", ans);
51 }
52 return 0;
53 }
