#include "dna.h"
#include <bits/stdc++.h>
#define fr first
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#define sc second
#define all(s) s.begin(), s.end()
//#define int long long
using namespace std;
const int nmax = 100005;
int n, pref[3][3][nmax];
void init(string a, string b) {
n = (int)a.size();
for(int i=0;i<n;i++){
if(a[i] == 'A') a[i] = '0';
else if(a[i] == 'C') a[i] = '1';
else a[i] = '2';
if(b[i] == 'A') b[i] = '0';
else if(b[i] == 'C') b[i] = '1';
else b[i] = '2';
}
for(int i=0;i<n;i++){
pref[a[i]-'0'][b[i]-'0'][i+1]++;
for(int j=0;j<=2;j++){
for(int t=0;t<=2;t++){
pref[j][t][i+1] += pref[j][t][i];
}
}
}
}
int get_distance(int x, int y) {
int dp[3][3];
for(int i=0;i<=2;i++){
for(int j=0;j<=2;j++){
dp[i][j] = (pref[i][j][y+1] - pref[i][j][x]);
}
}
int ans = 0;
for(int i=0;i<=2;i++){
int cnt1 = dp[i][0] + dp[i][1] + dp[i][2];
int cnt2 = dp[0][i] + dp[1][i] + dp[2][i];
if(cnt1 != cnt2) return -1;
}
for(int i=0;i<=2;i++){
for(int j=i+1;j<=2;j++){
int curr = min(dp[i][j], dp[j][i]);
ans += curr;
dp[i][j] -= curr;
dp[j][i] -= curr;
}
}
int cnt = 0;
for(int i=0;i<=2;i++){
for(int j=i+1;j<=2;j++){
ans += (dp[i][j] + dp[j][i]);
if(dp[i][j] + dp[j][i] > 0) cnt = 1;
}
}
if(cnt == 1) ans--;
return ans;
}
