#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
typedef long long ll;
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
int n;
int M = 100'010;
vector<int> A(M), B(M);
vector<vector<vector<int>>> prefix(M, vector<vector<int>>(3, vector<int>(3, 0)));
vector<vector<int>> prefA(M, vector<int>(3, 0)), prefB(M, vector<int>(3, 0));
int change(char c) {
if(c=='A') return 0;
if(c=='T') return 1;
return 2;
}
void init(string a, string b) {
n = a.size();
for(int i=0; i<n; ++i) A[i+1] = change(a[i]);
for(int i=0; i<n; ++i) B[i+1] = change(b[i]);
for(int i=1; i<=n; ++i) {
for(int x=0; x<3; ++x) for(int y=0; y<3; ++y) prefix[i][x][y] = prefix[i-1][x][y];
prefix[i][A[i]][B[i]]++;
for(int x=0; x<3; ++x) for(int y=0; y<3; ++y) prefA[i][x] += prefix[i][x][y];
for(int x=0; x<3; ++x) for(int y=0; y<3; ++y) prefB[i][x] += prefix[i][y][x];
}
}
int get_distance(int l, int r) {
++l; ++r;
vector<vector<int>> t(3, vector<int>(3, 0));
for(int x=0; x<3; ++x) for(int y=0; y<3; ++y) t[x][y] = prefix[r][x][y] - prefix[l-1][x][y];
for(int x=0; x<3; ++x) if(prefA[r][x]-prefA[l-1][x] != prefB[r][x] - prefB[l-1][x]) return -1;
int ans = 0;
ans += min(t[0][1], t[1][0]) + min(t[1][2], t[2][1]) + min(t[0][2], t[2][0]);
ans += 2*abs(t[0][1]-t[1][0]);
return ans;
}
/*int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, q;
cin >> n >> q;
string a,b;
cin >> a >> b;
init(a,b);
while(q--) {
int l,r;
cin >> l >> r;
cout << get_distance(l,r) << "\n";
}
return 0;
}*/
