//#include "parks.h"
#include<iostream>
#include<vector>
#include<queue>
#include<deque>
#include<string>
#include<fstream>
#include<algorithm>
#include <iomanip>
#include<map>
#include <set>
#include <unordered_map>
#include <stack>
#include <unordered_set>
#include <cmath>
#include <cstdint>
#include <cassert>
#include <bitset>
#include <random>
#include <chrono>
#include <cstring>
#include <variant>
#define shit short int
#define ll long long
#define ld long double
//#define int ll
#define For(i, n) for(int i = 0; i < (int)n; i++)
#define ffor(i, a, n) for(int i = (int)a; i < (int)n; i++)
#define rfor(i, n) for(int i = (int)n; i >= (int)0; i--)
#define rffor(i, a, n) for(int i = (int)n; i >= (int)a; i--)
#define vec vector
#define ff first
#define ss second
#define pb push_back
#define pii pair<int, int>
#define pld pair<ld, ld>
#define NEK 2000000000
#define mod 1000000007
#define mod2 1000000009
#define rsz resize
#define prv 43
#define prv2 47
#define D 8
#define trav(a,x) for (auto& a: x)
#define pb push_back
#define ub upper_bound
#define lb lower_bound
#define all(x) (x).begin(), (x).end()
#define sig 0.0000001
using namespace std;
class intervalac {
int n;
vec<int> l, r, in;
void update(int s) {
in[s] = in[s * 2] + in[s * 2 + 1];
return;
}
public:
void postav(int vel) {
n = 1;
while (n < vel) n *= 2;
l.resize(2 * n); r.resize(2 * n); in.resize(2 * n, 0);
For(i, n) {
l[i + n] = r[i + n] = i;
}
rffor(i, 1, (n - 1)) {
l[i] = l[i * 2];
r[i] = r[i * 2 + 1];
}
return;
}
void zmen(int a, int b) {
a += n;
in[a] += b;
a /= 2;
while (a) {
update(a);
a /= 2;
}
return;
}
int daj(int a, int b, int s = 1) {
if (l[s] > b || r[s] < a) return 0;
if (a <= l[s] && r[s] <= b) return in[s];
return daj(a, b, s * 2) + daj(a, b, s * 2 + 1);
}
};
int n;
vec<intervalac> seg;
void init(string a, string b) {
n = a.size();
seg.resize(9);
For(i, 9) {
seg[i].postav(n);
}
For(i, n) {
int hod = 0;
if (a[i] == 'C') hod = 1;
if (a[i] == 'T') hod = 2;
hod *= 3;
if (b[i] == 'C') hod++;
if (b[i] == 'T') hod += 2;
seg[hod].zmen(i, 1);
}
return;
}
int get_distance(int x, int y) {
int vys = (y - x);
vec<int> poc(9, 0);
int pocital = 0;
vec<int> pp1(3, 0), pp2(3, 0);
For(i, 3) {
For(j, 3) {
int hod = i * 3 + j;
poc[i * 3 + j] = seg[hod].daj(x, y);
pp1[i] += poc[i * 3 + j];
pp2[j] += poc[i * 3 + j];
}
}
For(i, 3) {
vys -= poc[i * 3 + i];
pocital += poc[i * 3 + i];
if (pp1[i] != pp2[i]) {
return -1;
}
}
if (x == y) return 0;
For(i, 3) {
For(j, 3) {
if (i == j) continue;
int hod1 = poc[i * 3 + j];
int hod2 = poc[j * 3 + i];
int k = min(hod1, hod2);
poc[i * 3 + j] -= k;
poc[j * 3 + i] -= k;
pocital += 2 * k;
vys -= k;
}
}
For(i, 3) {
For(j, 3) {
if (i == j) continue;
int k = 0;
for (; k < 3; k++) {
if (k != i && k != j) break;
}
int hod1 = i * 3 + j;
int hod2 = k * 3 + i;
int hod3 = j * 3 + k;
int mm = min(min(poc[hod1], poc[hod2]), poc[hod3]);
poc[hod1] -= mm;
poc[hod2] -= mm;
poc[hod3] -= mm;
pocital += 3 * mm;
vys -= mm;
}
}
if (pocital == (y - x + 1)) vys++;
return vys;
}
/*
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n; cin >> n;
int q; cin >> q;
string a, b; cin >> a >> b;
init(a, b);
For(i, q) {
int x, y; cin >> x >> y;
cout << get_distance(x, y) << '\n';
}
return 0;
}*/
