#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
//#include "dna.h"
const ll maxN = 1e5+10;
ll pref[maxN][3][3];
ll gt(char a) {
if(a=='A')return 0;
if(a=='T')return 1;
return 2;
}
void init(string a, string b) {
ll n=a.size();
for(int i = 0; i < maxN; i++) for(int x = 0; x < 3; x++)for(int z = 0; z < 3; z++)pref[i][x][z]=0;
for(int i = 1; i <= n; i++) {
ll v1 = gt(a[i-1]), v2=gt(b[i-1]);
for(int x = 0; x < 3; x++)for(int z = 0; z < 3; z++) pref[i][x][z]=pref[i-1][x][z];
pref[i][v1][v2]++;
}
}
int get_distance(int ind1, int ind2) {
ll res=0;
ll vals[3][3];
ll a = 0, b = 0, c = 0;
ll aa = 0, bb = 0, cc = 0;
for(int i = 0; i < 3; i++)for(int x = 0; x < 3; x++)vals[i][x]=pref[ind2+1][i][x]-pref[ind1][i][x];
for(int i = 0; i < 3; i++)for(int x = 0; x < 3; x++) {
if(i==0) {
a+=vals[i][x];
}
else if(i==1) {
b+=vals[i][x];
}
else if(i==2) {
c+=vals[i][x];
}
if(x==0) {
aa+=vals[i][x];
}
else if(x==1) {
bb+=vals[i][x];
}
else if(x==2) {
cc+=vals[i][x];
}
}
if(a!=aa||b!=bb||c!=cc) {
return -1;
}
for(int i = 0; i < 3; i++)for(int x = i+1; x < 3; x++) {
ll mn = min(vals[i][x], vals[x][i]);
vals[i][x]-=mn;vals[x][i]-=mn;
res+=mn;
}
res+=2*(vals[0][2]+vals[0][1]);
return res;
}
