#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int pref1[N],pref2[N],pref3[N],pref4[N];
void init(string a, string b) {
int n=a.size();
pref1[0]=0;
for(int i=0;i<n;i++){
pref1[i+1]=pref1[i];
if(a[i]=='A' && b[i]=='T'){
pref1[i+1]++;
}
if(a[i]=='T' && b[i]=='A'){
pref1[i+1]--;
}
}
pref2[0]=0;
for(int i=0;i<n;i++){
pref2[i+1]=pref2[i];
if(a[i]=='T' && b[i]=='C'){
pref2[i+1]++;
}
if(a[i]=='C' && b[i]=='T'){
pref2[i+1]--;
}
}
pref3[0]=0;
for(int i=0;i<n;i++){
pref3[i+1]=pref3[i];
if(a[i]=='C' && b[i]=='A'){
pref3[i+1]++;
}
if(a[i]=='A' && b[i]=='C'){
pref3[i+1]--;
}
}
pref4[0]=0;
for(int i=0;i<n;i++){
pref4[i+1]=pref4[i];
if(a[i]==b[i]){
pref4[i+1]++;
}
}
}
int get_distance(int x, int y) {
int sz=y-x+1;
x++;
y++;
x--;
int a1=pref1[y]-pref1[x];
int b1=pref2[y]-pref2[x];
int c1=pref3[y]-pref3[x];
int d1=pref4[y]-pref4[x];
/*
cout<<"a1: "<<a1<<endl;
cout<<"b1: "<<b1<<endl;
cout<<"c1: "<<c1<<endl;
*/
if(a1==b1 && b1==c1 && c1==a1){
return (sz-abs(a1)-abs(b1)-abs(c1)-abs(d1))/2+(abs(a1)+abs(b1)+abs(c1))/3*2;
}
return -1;
}
