#include <bits/stdc++.h>
#include "dna.h"
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
using ll = long long;
using ii = pair<int, int>;
using vi = vector<int>;
#define pb push_back
#define pp pop_back
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define lb lower_bound
#define ub upper_bound
typedef tree<int, null_type, less<int>, rb_tree_tag,
tree_order_statistics_node_update> indexed_set;
int P[100001][3], Pr[100001][3];
int M[100001][3], A[100001][3][3];
string S, T; int N;
void init(string a, string b) {
S = a, T = b; N = S.length();
vector<int> U, V;
for(int l = 0; l < N; l++) {
if(S[l] == 'A') U.pb(0);
if(S[l] == 'C') U.pb(1);
if(S[l] == 'T') U.pb(2);
if(T[l] == 'A') V.pb(0);
if(T[l] == 'C') V.pb(1);
if(T[l] == 'T') V.pb(2);
}
for(int l = 0; l < N; l++) {
P[l][U[l]]++; Pr[l][V[l]]++;
M[l][U[l]] += (S[l] != T[l]);
A[l][U[l]][V[l]]++;
for(int i = 0; i < 3 && l > 0; i++) {
P[l][i] += P[l - 1][i];
Pr[l][i] += Pr[l - 1][i];
M[l][i] += M[l - 1][i];
for(int j = 0; j < 3; j++)
A[l][i][j] += A[l - 1][i][j];
}
}
}
int get_distance(int x, int y) {
for(int l = 0; l < 3; l++) {
int X = P[y][l], Y = Pr[y][l];
if(x) X -= P[x - 1][l], Y -= Pr[x - 1][l];
if(X != Y) return -1;
}
int best = 1e9 + 7;
for(int l = 0; l < 3; l++) {
int res = M[y][l];
if(x) res -= M[x - 1][l];
int X = (l + 1) % 3, Y = (l + 2) % 3;
int U = M[y][X], V = M[y][Y];
if(x) U -= M[x - 1][X], V -= M[x - 1][Y];
int u = A[y][l][X], uu = A[y][X][l];
if(x) u -= A[x - 1][l][X], uu -= A[x - 1][X][l];
int v = A[y][l][Y], vv = A[y][Y][l];
if(x) v -= A[x - 1][l][Y], vv -= A[x - 1][Y][l];
U -= min(u, uu), V -= min(v, vv);
res += min(U, V);
best = min(best, res);
}
return best;
}
