#include "dna.h"
#include <bits/stdc++.h>
#define ll int
#define vll vector<ll>
#define pb push_back
#define bc back()
using namespace std;
const ll N=2e5+7;
ll pref[3][3][N];
ll sum[3][N];
ll sum2[3][N];
vll s,s2;
void init(std::string a, std::string b) {
map<char,ll> mp;
mp['A']=0;
mp['C']=1;
mp['T']=2;
for(int i=0;i<(ll)a.size();i++){
s.pb(mp[a[i]]);
s2.pb(mp[b[i]]);
sum[s.bc][i]++;
sum2[s2.bc][i]++;
if(s.bc!=s2.bc)pref[s.bc][s2.bc][i]++;
if(i==0)continue;
for(int j=0;j<3;j++){
for(int q=0;q<3;q++){
pref[j][q][i]+=pref[j][q][i-1];
}
}
for(int j=0;j<3;j++)sum[j][i]+=sum[j][i-1];
for(int j=0;j<3;j++)sum2[j][i]+=sum2[j][i-1];
}
}
int get_distance(int x, int y) {
ll i,j,q;
for(i=0;i<3;i++){
if(x==0){
if(sum[i][y]!=sum2[i][y])return -1;
continue;
}
if(sum[i][y]-sum[i][x-1]!=sum2[i][y]-sum2[i][x-1])return -1;
}
ll ans=0;
ll v[3][3];
memset(v,0,sizeof(v));
// edges
for(i=0;i<3;i++){
for(j=0;j<3;j++){
if(i==j)continue;
ll a;
if(x) a=pref[i][j][x-1];
else a=0;
v[i][j]=pref[i][j][y];
v[i][j]-=a;
ans+=v[i][j];
}
}
// two cycles
for(i=0;i<3;i++){
for(j=i+1;j<3;j++){
ll mn=min(v[i][j],v[j][i]);
ans-=mn;
v[i][j]-=mn;
v[j][i]-=mn;
}
}
//three cycles
for(i=0;i<3;i++){
for(j=0;j<3;j++){
if(i==j)continue;
for(q=0;q<3;q++){
if(i==q || j==q)continue;
ll mn=min(v[i][j],min(v[j][q],v[q][i]));
ans-=mn;
v[i][j]-=mn;
v[j][q]-=mn;
v[q][i]-=mn;
}
}
}
return ans;
}
