#include "dna.h"
//#include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
namespace{
const int mxn=1e5+5;
vector<vector<vector<int>>> pre(mxn,vector<vector<int>>(3,vector<int>(3)));
vector<vector<int>> prea(mxn,vector<int>(3));
vector<vector<int>> preb(mxn,vector<int>(3));
}
void init(std::string A, std::string B) {
int n=(int)A.size();
map<char,int> mp;
mp['A']=0;
mp['C']=1;
mp['T']=2;
vector<int> a(n+1),b(n+1);
for(int i=1;i<=n;i++){
a[i]=mp[A[i-1]];
b[i]=mp[B[i-1]];
}
for(int i=1;i<=n;i++){
pre[i][b[i]][a[i]]++;
for(int j=0;j<3;j++){
for(int k=0;k<3;k++){
pre[i][j][k]+=pre[i-1][j][k];
}
}
prea[i][a[i]]++;
preb[i][b[i]]++;
for(int j=0;j<3;j++){
prea[i][j]+=prea[i-1][j];
preb[i][j]+=preb[i-1][j];
}
}
}
int get_distance(int x, int y) {
x++;
y++;
for(int j=0;j<3;j++){
if((prea[y][j]-prea[x-1][j])!=(preb[y][j]-preb[x-1][j])) return -1;
}
vector<vector<int>> res(3,vector<int>(3));
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
res[i][j]=pre[y][i][j]-pre[x-1][i][j];
}
}
int ans=0;
for(int i=0;i<3;i++){
for(int j=i+1;j<3;j++){
int mn=min(res[i][j],res[j][i]);
ans+=mn;
res[i][j]-=mn;
res[j][i]-=mn;
}
}
if(res[0][1]>0){
int val=res[0][1];
if(res[1][2]!=val or res[2][0]!=val) return -1;
if(res[1][0]!=0 or res[0][2]!=0 or res[2][1]!=0) return -1;
ans+=res[0][1]*2;
}
else if(res[1][0]>0){
int val=res[1][0];
if(res[0][2]!=val or res[2][1]!=val) return -1;
if(res[0][1]!=0 or res[1][2]!=0 or res[2][0]!=0) return -1;
ans+=res[1][0]*2;
}
return ans;
}
