#define ll long long
#include <bits/stdc++.h>
using namespace std;
int n;
string a1,b1;
vector<int> V;
map<char,vector<int>> M;
map<char,vector<int>> M1;
void init(string a,string b){
a1=a;b1=b;
V.push_back(0);
for(int i=0;i<a1.size();i++){
if(a1[i]!=b1[i]){
V.push_back(V[i]+1);
}else{
V.push_back(V[i]);
}
}
M['C'].push_back(0);
M['T'].push_back(0);
M['A'].push_back(0);
M1['C'].push_back(0);
M1['T'].push_back(0);
M1['A'].push_back(0);
for(int i=0;i<a1.size();i++){
if(a1[i]=='C'){
M[a1[i]].push_back(M[a1[i]][i]+1);
M['T'].push_back(M['T'][i]);
M['A'].push_back(M['A'][i]);
}
if(a1[i]=='A'){
M[a1[i]].push_back(M[a1[i]][i]+1);
M['T'].push_back(M['T'][i]);
M['C'].push_back(M['C'][i]);
}
if(a1[i]=='T'){
M[a1[i]].push_back(M[a1[i]][i]+1);
M['A'].push_back(M['A'][i]);
M['C'].push_back(M['C'][i]);
}
}
for(int i=0;i<a1.size();i++){
if(b1[i]=='C'){
M1[b1[i]].push_back(M1[b1[i]][i]+1);
M1['T'].push_back(M1['T'][i]);
M1['A'].push_back(M1['A'][i]);
}
if(b1[i]=='A'){
M1[b1[i]].push_back(M1[b1[i]][i]+1);
M1['T'].push_back(M1['T'][i]);
M1['C'].push_back(M1['C'][i]);
}
if(b1[i]=='T'){
M1[b1[i]].push_back(M1[b1[i]][i]+1);
M1['A'].push_back(M1['A'][i]);
M1['C'].push_back(M1['C'][i]);
}
}
}
int get_distance(int x, int y){
x++;
y++;
int res=V[y]-V[x-1];
int n1=M['C'][y]-M['C'][x-1];
int n2=M['T'][y]-M['T'][x-1];
int n3=M['A'][y]-M['A'][x-1];
int m1=M1['C'][y]-M1['C'][x-1];
int m2=M1['T'][y]-M1['T'][x-1];
int m3=M1['A'][y]-M1['A'][x-1];
if(n1==m1 && n2==m2 && n3==m3){
if(res%2==0)return res/2;
return res/2+1;
}
return -1;
}
