// In the name of Allah
#include <bits/stdc++.h>
#include "dna.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define endl '\n'
#define sep ' '
#define F first
#define S second
#define all(x) (x).begin(),(x).end()
#define len(x) ((ll) (x).size())
#define pb push_back
#define Mp make_pair
const int maxn = 2e5 + 7;
int n;
int A1[maxn], A2[maxn];
pair<int, pii> sm1[maxn], sm2[maxn];
int smx[3][3][maxn]; int val[3][3];
bool ok(int l, int r) {
if (sm1[r].F - sm1[l].F != sm2[r].F - sm2[l].F) return 0;
if (sm1[r].S.F - sm1[l].S.F != sm2[r].S.F - sm2[l].S.F) return 0;
if (sm1[r].S.S - sm1[l].S.S != sm2[r].S.S - sm2[l].S.S) return 0;
return 1;
}
void init(string a, string b) {
n = len(a);
for (int i = 1; i <= n; i++) {
if (a[i - 1] == 'A') A1[i] = 0;
else if (a[i - 1] == 'T') A1[i] = 1;
else if (a[i - 1] == 'C') A1[i] = 2;
if (b[i - 1] == 'A') A2[i] = 0;
else if (b[i - 1] == 'T') A2[i] = 1;
else if (b[i - 1] == 'C') A2[i] = 2;
}
for (int i = 1; i <= n; i++) {
sm1[i].F = sm1[i - 1].F + (A1[i] == 0);
sm1[i].S.F = sm1[i - 1].S.F + (A1[i] == 1);
sm1[i].S.S = sm1[i - 1].S.S + (A1[i] == 2);
sm2[i].F = sm2[i - 1].F + (A2[i] == 0);
sm2[i].S.F = sm2[i - 1].S.F + (A2[i] == 1);
sm2[i].S.S = sm2[i - 1].S.S + (A2[i] == 2);
}
for (int R1 = 0; R1 < 3; R1++) {
for (int R2 = 0; R2 < 3; R2++) {
for (int i = 1; i <= n; i++) {
smx[R1][R2][i] = smx[R1][R2][i - 1] + (A1[i] == R1 && A2[i] == R2);
}
}
}
}
int get_distance(int l, int r) {
r++;
if (!ok(l, r)) return -1;
for (int R1 = 0; R1 < 3; R1++) {
for (int R2 = 0; R2 < 3; R2++) {
val[R1][R2] = smx[R1][R2][r] - smx[R1][R2][l];
}
}
ll res = 0;
ll d1 = min(val[0][1], val[1][0]);
val[0][1] -= d1; val[1][0] -= d1;
res += d1;
ll d2 = min(val[0][2], val[2][0]);
val[0][2] -= d2; val[2][0] -= d2;
res += d2;
ll d3 = min(val[1][2], val[2][1]);
val[1][2] -= d3; val[2][1] -= d3;
res += d3;
res += 2 * (val[0][1] + val[1][0]);
return res;
}
