#include "dna.h"
#include <bits/stdc++.h>
#define sz(x) ((int)(x).size())
using namespace std;
const int N = 100500;
int ga[3][3][N];
void init(std::string a, std::string b) {
vector<int> c2i(128);
c2i['A'] = 0;
c2i['T'] = 1;
c2i['C'] = 2;
for (int i = 0; i < sz(a); ++i) {
for (int x = 0; x < 3; ++x)
for (int y = 0; y < 3; ++y)
ga[x][y][i + 1] = ga[x][y][i];
ga[c2i[a[i]]][c2i[b[i]]][i + 1]++;
}
}
int get_distance(int l, int r) {
int a[3][3];
++r;
for (int i = 0; i < 3; ++i)
for (int j = 0; j < 3; ++j)
a[i][j] = ga[i][j][r] - ga[i][j][l];
int ans = 0;
for (int i = 0; i < 3; ++i)
for (int j = 0; j < i; ++j) {
int x = min(a[i][j], a[j][i]);
ans += x;
a[i][j] -= x;
a[j][i] -= x;
}
if (a[0][1] != a[1][2] || a[1][2] != a[2][0]) return -1;
if (a[1][0] != a[2][1] || a[2][1] != a[0][2]) return -1;
ans += a[0][1] * 2;
ans += a[1][0] * 2;
return ans;
}
