#include "dna.h"
#include "bits/stdc++.h"
using namespace std;
string A,B;
void init(string a,string b)
{
A=a;
B=b;
}
int get_distance(int x,int y)
{
string sa="",sb="";
for(int i=x;i<=y;i++) sa+=A[i];
for(int i=x;i<=y;i++) sb+=B[i];
vector<int>ca(3,0),cb(3,0);
for(char c:sa)
{
if(c=='A') ca[0]++;
if(c=='C') ca[1]++;
if(c=='T') ca[2]++;
}
for(char c:sb)
{
if(c=='A') cb[0]++;
if(c=='C') cb[1]++;
if(c=='T') cb[2]++;
}
for(int i=0;i<3;i++) if(ca[i]!=cb[i]) return -1;
int AC=0;
int CA=0;
int AT=0;
int TA=0;
int CT=0;
int TC=0;
for(int i=x;i<=y;i++){
if(A[i]==B[i]) continue;
if(B[i]=='A'&&A[i]=='C') AC++;
if(B[i]=='C'&&A[i]=='A') CA++;
if(B[i]=='A'&&A[i]=='T') AT++;
if(B[i]=='T'&&A[i]=='A') TA++;
if(B[i]=='C'&&A[i]=='T') CT++;
if(B[i]=='T'&&A[i]=='C') TC++;
}
int res=0;
int s1=min(AC,CA);
int s2=min(AT,TA);
int s3=min(CT,TC);
res+=s1;
res+=s2;
res+=s3;
AC-=s1;
CA-=s1;
AT-=s2;
TA-=s2;
CT-=s3;
TC-=s3;
int add=(AC+CA+AT+TA+CT+TC);
return (res+((add/3)*2));
}
