#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma,bmi,bmi2")
#include <bits/stdc++.h>
using namespace std;
int n, pref[3][3][100001], cnt[3][3];
void init(string A, string B)
{
n = A.size();
for (int i = 0, a, b; i < n; i++)
{
for (a = 0; a < 3; a++)
for (b = 0; b < 3; b++)
pref[a][b][i + 1] = pref[a][b][i];
a = (A[i] == 'C') + 2 * (A[i] == 'T');
b = (B[i] == 'C') + 2 * (B[i] == 'T');
pref[a][b][i + 1]++;
}
}
int get_distance(int x, int y)
{
for (int a = 0; a < 3; a++)
for (int b = 0; b < 3; b++)
cnt[a][b] = pref[a][b][y + 1] - pref[a][b][x];
for (int i = 0; i < 3; i++)
if (cnt[i][0] + cnt[i][1] + cnt[i][2] != cnt[0][i] + cnt[1][i] + cnt[2][i])
return -1;
if (cnt[0][1] < cnt[1][0])
swap(cnt[0][1], cnt[1][0]);
return 2 * cnt[0][1] - cnt[1][0] + min(cnt[1][2], cnt[2][1]) + min(cnt[2][0], cnt[0][2]);
}
