#include"bits/stdc++.h"
#include "dna.h"
using namespace std;
const int sz = 1e5 + 5;
map<char, int> en;
int p[sz][3][3];
int n;
string s, t;
void init(string a, string b) {
n = a.size();
s = ' ' + a, t = ' ' + b;
en['A'] = 0, en['T'] = 1, en['C'] = 2;
for (int i = 1; i <= n; i ++) {
if (s[i] != t[i]) {
int a = en[s[i]];
int b = en[t[i]];
p[i][a][b] ++;
}
for (int j = 0; j < 3; j ++) {
for (int k = 0; k < 3; k ++) {
p[i][j][k] += p[i - 1][j][k];
}
}
}
}
int get_distance(int x, int y) {
x ++, y ++;
bool v[3][3] {};
int cn[3] {};
int d = 0;
for (int i = 0; i < 3; i ++) {
for (int j = 0; j < 3; j ++) {
int cni = p[y][i][j] - p[x - 1][i][j];
int cnj = p[y][j][i] - p[x - 1][j][i];
if (cni >= cnj && !v[j][i]) {
cn[i] += cni - cnj;
v[i][j] = true;
d += cnj;
}
}
}
if (cn[0] == cn[1] && cn[1] == cn[2]) {
d += cn[0] * 2;
} else {
return -1;
}
return d;
}
