#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
#define forn(i,n) for(int i=0; i<n; ++i)
#define pb push_back
#define all(x) x.begin(), x.end()
const int N=1e5+5;
int A[N], C[N], T[N];
int AA[N], AT[N], AC[N];
int CA[N], CT[N], CC[N];
int TA[N], TT[N], TC[N];
void init(string a, string b) {
int n=a.size();
forn(i,n) {
A[i+1]=A[i]+(a[i]=='A')-(b[i]=='A');
C[i+1]=C[i]+(a[i]=='C')-(b[i]=='C');
T[i+1]=T[i]+(a[i]=='T')-(b[i]=='T');
AT[i+1]=AT[i] + ( (a[i]=='A') && (b[i]=='T') );
AC[i+1]=AC[i] + ( (a[i]=='A') && (b[i]=='C') );
CT[i+1]=CT[i] + ( (a[i]=='C') && (b[i]=='T') );
TC[i+1]=TC[i] + ( (a[i]=='T') && (b[i]=='C') );
CA[i+1]=CA[i] + ( (a[i]=='C') && (b[i]=='A') );
TA[i+1]=TA[i] + ( (a[i]=='T') && (b[i]=='A') );
}
}
int get_distance(int x, int y) {
int a = A[y+1]-A[x];
if (a) return -1;
int c = C[y+1]-C[x];
if (c) return -1;
int t = T[y+1]-T[x];
if (t) return -1;
int at=AT[y+1]-AT[x];
int ct=CT[y+1]-CT[x];
int ac=AC[y+1]-AC[x];
int tc=TC[y+1]-TC[x];
int ca=CA[y+1]-CA[x];
int ta=TA[y+1]-TA[x];
int ans=0;
int z;
z = min(at,ta);
ans+=z;
at-=z;
ta-=z;
z = min(ac,ca);
ans+=z;
ac-=z;
ca-=z;
z = min(ct,tc);
ans+=z;
ct-=z;
tc-=z;
ans+=2*(ac+ca);
return ans;
}
