#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ii pair<ll,ll>
#define fi first
#define se second
#define puf push_front
#define pof pop_front
#define pub push_back
#define pob pop_back
#define rep(x,s,e) for (auto x=s-(s>e);x!=e-(s>e);s<e?x++:x--)
#define all(x) (x).begin(),(x).end()
#define sz(x) (int) (x).size()
int n;
int cnta_s[100005];
int cntt_s[100005];
int cnta_t[100005];
int cntt_t[100005];
int cntat[100005];
int cntta[100005];
int cntac[100005];
int cntca[100005];
int cnttc[100005];
int cntct[100005];
void init(std::string s, std::string t) {
n=sz(s);
rep(x,0,n) cnta_s[x+1]=cnta_s[x]+(s[x]=='A');
rep(x,0,n) cntt_s[x+1]=cntt_s[x]+(s[x]=='T');
rep(x,0,n) cnta_t[x+1]=cnta_t[x]+(t[x]=='A');
rep(x,0,n) cntt_t[x+1]=cntt_t[x]+(t[x]=='T');
rep(x,0,n) cntat[x+1]=cntat[x]+(s[x]=='A' && t[x]=='T');
rep(x,0,n) cntta[x+1]=cntta[x]+(s[x]=='T' && t[x]=='A');
rep(x,0,n) cntac[x+1]=cntac[x]+(s[x]=='A' && t[x]=='C');
rep(x,0,n) cntca[x+1]=cntca[x]+(s[x]=='C' && t[x]=='A');
rep(x,0,n) cnttc[x+1]=cnttc[x]+(s[x]=='T' && t[x]=='C');
rep(x,0,n) cntct[x+1]=cntct[x]+(s[x]=='C' && t[x]=='T');
}
int get_distance(int l, int r) {
if (cnta_s[r+1]-cnta_s[l]!=cnta_t[r+1]-cnta_t[l]) return -1;
if (cntt_s[r+1]-cntt_s[l]!=cntt_t[r+1]-cntt_t[l]) return -1;
int at=cntat[r+1]-cntat[l];
int ta=cntta[r+1]-cntta[l];
int ac=cntac[r+1]-cntac[l];
int ca=cntca[r+1]-cntca[l];
int tc=cnttc[r+1]-cnttc[l];
int ct=cntct[r+1]-cntct[l];
//cout<<at<<" "<<ta<<" "<<ac<<" "<<ca<<" "<<tc<<" "<<ct<<endl;
int ans=0;
int temp;
temp=min(at,ta);
ans+=temp;
at-=temp,ta-=temp;
temp=min(ac,ca);
ans+=temp;
ac-=temp,ca-=temp;
temp=min(tc,ct);
ans+=temp;
tc-=temp,ct-=temp;
ans+=2*(at+ta);
return ans;
}
