#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
int n, p[100001][3][3];
void init(std::string a, std::string b) {
n = a.size();
map<char, int> tm;
tm['A'] = 0;
tm['T'] = 1;
tm['C'] = 2;
for (int i = 0; i < n; i++) {
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 3; k++) p[i + 1][j][k] = p[i][j][k];
}
int j = tm[a[i]], k = tm[b[i]];
p[i + 1][j][k]++;
}
}
int get_distance(int x, int y) {
y++;
vector<int> ta(3);
int ans = y - x;
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 3; k++) {
int v = p[y][j][k] - p[x][j][k];
ta[j] += v;
ta[k] -= v;
if (j == k) ans -= v;
}
}
for (int tx: ta) {
if (tx != 0) {
return -1;
}
}
int ttx = n;
for (int j = 0; j < 3; j++) {
for (int k = j + 1; k < 3; k++) {
int tx = p[y][j][k] - p[x][j][k], ty = p[y][k][j] - p[x][k][j];
ans -= min(tx, ty);
ttx = min(ttx, max(tx, ty) - min(tx, ty));
}
}
return ans - ttx;
}
