#include<bits/stdc++.h>
#include "dna.h"
using namespace std;
#define pii pair<int,int>
#define pb push_back
#define rep(i,n) for(int i=0;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
int pre[100005][6];
int acta[100005][3],actb[100005][3];
int n;
char trans(char p)
{
return p=='A'?'a':(p=='C'?'b':'c');
}
void init(string a,string b)
{
a=" "+a;b=" "+b;
n=(int)a.size()-1;
rep1(i,n)
{
a[i]=trans(a[i]);
b[i]=trans(b[i]);
}
rep1(i,n)
{
rep(j,6){pre[i][j]=pre[i-1][j];}
rep(j,3){acta[i][j]=acta[i-1][j];}
acta[i][a[i]-'a']++;
rep(j,3){actb[i][j]=actb[i-1][j];}
actb[i][b[i]-'a']++;
if(a[i]==b[i]){continue;}
if(a[i]=='a'&&b[i]=='b'){pre[i][0]++;}
if(a[i]=='a'&&b[i]=='c'){pre[i][1]++;}
if(a[i]=='b'&&b[i]=='a'){pre[i][2]++;}
if(a[i]=='b'&&b[i]=='c'){pre[i][3]++;}
if(a[i]=='c'&&b[i]=='a'){pre[i][4]++;}
if(a[i]=='c'&&b[i]=='b'){pre[i][5]++;}
}
}
int get_distance(int x,int y)
{
x++,y++;
rep(i,3)
{
if(acta[y][i]-acta[x-1][i]!=actb[y][i]-actb[x-1][i])
{
return -1;
}
}
int npre[6];
rep(i,6)
{
npre[i]=pre[y][i]-pre[x-1][i];
}
int act=npre[0]+npre[2]-2*min(npre[0],npre[2]);
if(act==0)
{
return npre[1];
}
return act*2;
}
