#include <bits/stdc++.h>
#include "dna.h"
using namespace std;
#define fi first
#define se second
#define _size(x) (int)x.size()
#define BIT(i, x) ((x >> i) & 1)
#define MASK(n) ((1 << n) - 1)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; i++)
#define FOR(i, a, b) for (int i = a, _b = (b); i <= _b; i++)
#define FORD(i, a, b) for (int i = a, _b = (b); i >= _b; i--)
#define FORB1(i, mask) for (int i = mask; i > 0; i ^= i & - i)
#define FORB0(i, n, mask) for (int i = ((1 << n) - 1) ^ mask; i > 0; i ^= i & - i)
#define FORALL(i, a) for (auto i: a)
#define fastio ios_base::sync_with_stdio(0); cin.tie(0);
vector<vector<vector<int>>> f;
void init(string a, string b) {
int n = _size(a);
vector<int> chA(n + 1), chB(n + 1);
f.resize(n + 1, vector<vector<int>>(3, vector<int>(3)));
FOR(i, 1, n) {
if (a[i - 1] == 'A') chA[i] = 0;
else if (a[i - 1] == 'T') chA[i] = 1;
else chA[i] = 2;
if (b[i - 1] == 'A') chB[i] = 0;
else if (b[i - 1] == 'T') chB[i] = 1;
else chB[i] = 2;
REP(j, 3) REP(z, 3) f[i][j][z] = f[i - 1][j][z];
f[i][chA[i]][chB[i]]++;
}
}
int get_distance(int x, int y) {
x++, y++;
vector<vector<int>> g(3, vector<int>(3));
REP(i, 3) REP(j, 3) g[i][j] = f[y][i][j] - f[x - 1][i][j];
int ans = 0;
REP(i, 3) REP(j, 3) {
int value = min(g[i][j], g[j][i]);
g[i][j] -= value;
if (i == j) continue;
g[j][i] -= value;
ans += value;
}
vector<pair<int, int>> vtx;
REP(i, 3) REP(j, 3) if (g[i][j]) vtx.push_back({i, j});
if (!_size(vtx)) return ans;
if (_size(vtx) != 3) return - 1;
int value = g[vtx[0].fi][vtx[0].se];
FORALL(e, vtx) if (g[e.fi][e.se] != value) return - 1;
FORALL(p, vtx) FORALL(q, vtx) {
if (p == q) continue;
if (p.fi == q.fi) return - 1;
int cnt = (p.fi == q.se) + (p.se == q.fi) + (p.se == q.se);
if (cnt != 1) return - 1;
}
return ans + value * 2;
}
