// Be Name Khoda //
#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
#define MAX(x, y) ((x) > (y) ? (x) : (y))
#define MIN(x, y) ((x) < (y) ? (x) : (y))
#define debug(x) cerr << "(" << (#x) << "): " << (x) << endl;
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
#define mp make_pair
typedef long long ll;
const int maxn5 = 1e5 + 10;
int n, ps[maxn5][3][3], cnt[3][3];
int get_ps(int l, int r, int i, int j){
return ps[r][i][j] - (l ? ps[l - 1][i][j] : 0);
}
int get_num(int ty, int l, int r, int x){
if(ty)
return get_ps(l, r, 0, x) + get_ps(l, r, 1, x) + get_ps(l, r, 2, x);
return get_ps(l, r, x, 0) + get_ps(l, r, x, 1) + get_ps(l, r, x, 2);
}
void init(std::string a, std::string b) {
n = a.size();
for(int i = 0; i < n; i++){
int x = a[i] == 'A' ? 0 : (a[i] == 'C' ? 1 : 2);
int y = b[i] == 'A' ? 0 : (b[i] == 'C' ? 1 : 2);
if(i){
for(int j = 0; j < 3; j++) for(int k = 0; k < 3; k++)
ps[i][j][k] = ps[i - 1][j][k];
}
ps[i][x][y]++;
}
}
int get_distance(int x, int y) {
for(int i = 0; i < 3; i++){
int num1 = get_num(0, x, y, i);
int num2 = get_num(1, x, y, i);
if(num1 != num2)
return -1;
}
memset(cnt, 0, sizeof cnt);
for(int i = 0; i < 3; i++) for(int j = 0; j < 3; j++)
cnt[i][j] = get_ps(x, y, i, j);
int eq = cnt[0][0] + cnt[1][1] + cnt[2][2];
int pr = 0;
for(int i = 0; i < 3; i++) for(int j = i + 1; j < 3; j++)
pr += min(cnt[i][j], cnt[j][i]);
return pr + (y - x + 1 - eq - pr * 2) / 3 * 2;
}
