#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 20;
int diff[maxn][3];
int cnt[maxn][3][3];
void init(string a, string b) {
int n = a.size();
for (int i = 1; i <= n; i++) {
for (int x = 0; x < 3; x++) {
diff[i][x] = diff[i - 1][x];
for (int y = 0; y < 3; y++) {
cnt[i][x][y] = cnt[i - 1][x][y];
}
}
int x = a[i - 1] == 'A' ? 0 : a[i - 1] == 'T' ? 1 : 2;
int y = b[i - 1] == 'A' ? 0 : b[i - 1] == 'T' ? 1 : 2;
cnt[i][x][y]++;
diff[i][x]++;
diff[i][y]--;
}
}
int get_distance(int lt, int rt) {
lt++;
rt++;
for (int x = 0; x < 3; x++) {
if (diff[rt][x] != diff[lt - 1][x]) {
return -1;
}
}
int res = 0;
for (int x = 0; x < 3; x++) {
for (int y = x + 1; y < 3; y++) {
res += min(cnt[rt][x][y] - cnt[lt - 1][x][y], cnt[rt][y][x] - cnt[lt - 1][y][x]);
}
}
res += abs((cnt[rt][0][1] - cnt[lt - 1][0][1]) - (cnt[rt][1][0] - cnt[lt - 1][1][0])) * 2;
return res;
}
