#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> dif, dif2;
vector<vector<int>> match;
void init(string a, string b){
int n = a.size();
dif.clear();
match.clear();
dif2.clear();
dif.resize(n + 1, vector<int> (3));
dif2.resize(n + 1, vector<int> (3));
match.resize(n + 1, vector<int> (3));
for (int i = 1; i <= n; i++){
match[i][0] = match[i - 1][0];
match[i][1] = match[i - 1][1];
match[i][2] = match[i - 1][2];
dif[i][0] = dif[i - 1][0];
dif[i][1] = dif[i - 1][1];
dif[i][2] = dif[i - 1][2];
dif2[i][0] = dif2[i - 1][0];
dif2[i][1] = dif2[i - 1][1];
dif2[i][2] = dif2[i - 1][2];
if (a[i - 1] == 'A') match[i][0]++;
else if (a[i - 1] == 'T')match[i][1]++;
else match[i][2]++;
if (b[i - 1] == 'A') match[i][0]--;
else if (b[i - 1] == 'T')match[i][1]--;
else match[i][2]--;
if (a[i - 1] == 'A' && b[i - 1] == 'T') dif[i][0]++;
else if (a[i - 1] == 'A' && b[i - 1] == 'C')dif[i][1]++;
else if (a[i - 1] == 'T' && b[i - 1] == 'C') dif[i][2]++;
if (a[i - 1] == 'T' && b[i - 1] == 'A') dif2[i][0]++;
else if (a[i - 1] == 'C' && b[i - 1] == 'A')dif2[i][1]++;
else if (a[i - 1] == 'C' && b[i - 1] == 'T') dif2[i][2]++;
}
}
int get_distance(int x, int y){
y++;
x++;
if (match[y][0] == match[x - 1][0] && match[y][1] == match[x - 1][1] && match[y][2] == match[x - 1][2]){
int ans = 0;
int tot = dif[y][0] - dif[x - 1][0] + dif2[y][0] - dif2[x - 1][0];
int one = min(dif[y][0] - dif[x - 1][0], dif2[y][0] - dif2[x - 1][0]);
ans += one;
tot += dif[y][1] - dif[x - 1][1] + dif2[y][1] - dif2[x - 1][1];
int two = min(dif[y][1] - dif[x - 1][1], dif2[y][1] - dif2[x - 1][1]);
ans += two;
tot += dif[y][2] - dif[x - 1][2] + dif2[y][2] - dif2[x - 1][2];
int three = min(dif[y][2] - dif[x - 1][2], dif2[y][2] - dif2[x - 1][2]);
ans += three;
ans += ((tot - 2 * one - 2 * two - 2 * three) / 3) * 2;
return ans;
}else return -1;
}
