#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
int n;
vector<vector<vector<int>>> pref;
void init(std::string a, std::string b) {
n = a.size();
pref.resize(n + 1, vector<vector<int>> (3, vector<int> (3)));
for (int i = 0; i < n; i++) {
pref[i + 1] = pref[i];
int a1;
if (a[i] == 'A') {
a1 = 0;
} else if (a[i] == 'C') {
a1 = 1;
} else {
a1 = 2;
}
int b1;
if (b[i] == 'A') {
b1 = 0;
} else if (b[i] == 'C') {
b1 = 1;
} else {
b1 = 2;
}
pref[i + 1][a1][b1]++;
}
}
int get_distance(int x, int y) {
vector<vector<int>> arr = pref[y + 1];
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
arr[i][j] -= pref[x][i][j];
}
}
vector<int> cnt1(3), cnt2(3);
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
cnt1[i] += arr[i][j];
cnt2[j] += arr[i][j];
}
}
if (cnt1 != cnt2) {
return -1;
}
for (int i = 0; i < 3; i++) {
arr[i][i] = 0;
}
int ans = 0;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
int mn = min(arr[i][j], arr[j][i]);
ans += mn;
arr[i][j] -= mn;
arr[j][i] -= mn;
}
}
assert(arr[0][1] == arr[1][2] && arr[1][2] == arr[2][0]);
assert(arr[1][0] == arr[2][1] && arr[2][1] == arr[0][2]);
ans += 2 * (arr[0][1] + arr[1][0]);
return ans;
}
