#include"dna.h"
#include <bits/stdc++.h>
using namespace std;
const int MAXN=1e5+5;
int pref[MAXN][6];
void init(string a,string b)
{
int n=a.length();
a=' '+a,b=' '+b;
for(int i=1;i<=n;i++)
{
for(int j=0;j<6;j++) pref[i][j]+=pref[i-1][j];
if(a[i]=='A'&&b[i]=='T') pref[i][0]++;
if(a[i]=='T'&&b[i]=='A') pref[i][3]++;
if(a[i]=='T'&&b[i]=='C') pref[i][1]++;
if(a[i]=='C'&&b[i]=='T') pref[i][4]++;
if(a[i]=='C'&&b[i]=='A') pref[i][2]++;
if(a[i]=='A'&&b[i]=='C') pref[i][5]++;
}
}
int get_distance(int x,int y)
{
x++,y++;
int a0=pref[y][0]-pref[x-1][0];
int a1=pref[y][1]-pref[x-1][1];
int a2=pref[y][2]-pref[x-1][2];
int a3=pref[y][3]-pref[x-1][3];
int a4=pref[y][4]-pref[x-1][4];
int a5=pref[y][5]-pref[x-1][5];
int u=min(a0,a3),v=min(a1,a4),w=min(a2,a5);
int ans=u+v+w;
a0-=u,a3-=u,a1-=v,a4-=v,a2-=w,a5-=w;
if(a0==a1&&a1==a2&&a3==a4&&a4==a5) return ans+max(a0,a3)*2;
return -1;
}
