#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5+23;
int n;
int a[N],b[N];
int pref[N][4][4];
void init(string s,string t){
n = s.size();
for(int i = 1; i <= n; i++){
if(s[i-1] == 'A') a[i] = 1;
else if(s[i-1] == 'C') a[i] = 2;
else a[i] = 3;
if(t[i-1] == 'A') b[i] = 1;
else if(t[i-1] == 'C') b[i] = 2;
else b[i] = 3;
}
for(int h = 1; h <= n; h++){
for(int i = 1; i <= 3; i++){
for(int j = 1; j <= 3; j++){
pref[h][i][j] = pref[h-1][i][j]+(a[h] == i && b[h] == j);
}
}
}
}
int sta[4][4];
int get_distance(int x,int y){
x++;
y++;
for(int i = 1; i <= 3; i++){
for(int j = 1; j <= 3; j++){
sta[i][j] = pref[y][i][j]-pref[x-1][i][j];
}
}
for(int i = 1; i <= 3; i++){
int s1 = 0;
for(int j = 1; j <= 3; j++) s1 += sta[i][j];
int s2 = 0;
for(int j = 1; j <= 3; j++) s2 += sta[j][i];
if(s1 != s2){
return -1;
}
}
int v1 = min(sta[1][2],sta[2][1]);
int v2 = min(sta[2][3],sta[3][2]);
int v3 = min(sta[1][3],sta[3][1]);
int dod = 2*abs(sta[1][2]-sta[2][1]);
return v1+v2+v3+dod;
}
