#include "dna.h"
#include<bits/stdc++.h>
using namespace std;
int pref[100005][15];
void init(std::string a, std::string b)
{
memset(pref,0,sizeof pref);
for(int i=1;i<=a.length();i++)
{
pref[i][0]=(a[i-1]=='A') + pref[i-1][0];
pref[i][1]=(b[i-1]=='A') + pref[i-1][1];
pref[i][2]=(a[i-1]=='T') + pref[i-1][2];
pref[i][3]=(b[i-1]=='T') + pref[i-1][3];
pref[i][4]=(a[i-1]=='C') + pref[i-1][4];
pref[i][5]=(b[i-1]=='C') + pref[i-1][5];
pref[i][6]=(a[i-1]=='A' && b[i-1]=='T') + pref[i-1][6];
pref[i][7]=(a[i-1]=='T' && b[i-1]=='A') + pref[i-1][7];
pref[i][8]=(a[i-1]=='T' && b[i-1]=='C') + pref[i-1][8];
pref[i][9]=(a[i-1]=='C' && b[i-1]=='T') + pref[i-1][9];
pref[i][10]=(a[i-1]=='C' && b[i-1]=='A') + pref[i-1][10];
pref[i][11]=(a[i-1]=='A' && b[i-1]=='C') + pref[i-1][11];
}
}
int sum(int l,int r,int id)
{
return pref[r][id]-pref[l-1][id];
}
int get_distance(int x, int y)
{
x++;y++;
if(sum(x,y,0)!=sum(x,y,1) || sum(x,y,2)!=sum(x,y,3) || sum(x,y,4)!=sum(x,y,5)) return -1;
int ans=0,rem=0;
for(int i=6;i<=10;i+=2)
{
int a=sum(x,y,i),b=sum(x,y,i+1);
ans+=min(a,b);
rem+=max(a,b)-min(a,b);
}
ans+=rem*2/3;
return ans;
}
