#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN=100005;
int N, p[MAXN], e[MAXN];
pair<int,int> a[MAXN], t[MAXN], c[MAXN];
map<pair<int,int>, int> dir;
void init(string x, string y){
N=x.size();
for(int i=0;i<N;i++){
if(x[i]=='A'){
a[i+1].first++;
}else if(x[i]=='T'){
t[i+1].first++;
}else{
c[i+1].first++;
}
if(y[i]=='A'){
a[i+1].second++;
}else if(y[i]=='T'){
t[i+1].second++;
}else{
c[i+1].second++;
}
}
for(auto &d:{a, t, c}){
for(int i=1;i<=N;i++){
d[i].first+=d[i-1].first;
d[i].second+=d[i-1].second;
}
}
for(int i=0;i<N;i++){
if(x[i]==y[i])continue;
if(dir[{y[i], x[i]}]){
p[i+1]++;
dir.erase({y[i], x[i]});
continue;
}
dir[{x[i], y[i]}]=i;
}
}
int get_distance(int x, int y){
x++;y++;
int cnt_a=a[y].first-a[x-1].first;
int cnt_a2=a[y].second-a[x-1].second;
int cnt_t=t[y].first-t[x-1].first;
int cnt_t2=t[y].second-t[x-1].second;
int cnt_c=c[y].first-c[x-1].first;
int cnt_c2=c[y].second-c[x-1].second;
if(cnt_a!=cnt_a2||cnt_t!=cnt_t2||cnt_c!=cnt_c2){
return -1;
}
int dom=p[y]-p[x-1];
return dom+(((y-x+1)-dom*2)/3)*2;
}
