#include <bits/stdc++.h>
using namespace std;
#define loop(x, i) for (int i = 0; i < x; i++)
#define pb push_back
#define ALL(x) begin(x), end(x)
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<vii> vvii;
vi sumAC, sumAT, sumCA, sumCT, sumTA, sumTC;
void init(string a, string b)
{
int n = a.size();
sumAC = sumAT = sumCA = sumCT = sumTA = sumTC = {0};
loop(n, i)
{
sumAC.pb(sumAC.back());
sumAT.pb(sumAT.back());
sumCA.pb(sumCA.back());
sumCT.pb(sumCT.back());
sumTA.pb(sumTA.back());
sumTC.pb(sumTC.back());
if (a[i] == b[i])
continue;
if (a[i] == 'A')
{
if (b[i] == 'C')
sumAC.back()++;
else
sumAT.back()++;
}
else if (a[i] == 'C')
{
if (b[i] == 'A')
sumCA.back()++;
else
sumCT.back()++;
}
else
{
if (b[i] == 'A')
sumTA.back()++;
else
sumTC.back()++;
}
}
}
int get_distance(int i, int j)
{
int AC = sumAC[j + 1] - sumAC[i];
int AT = sumAT[j + 1] - sumAT[i];
int CA = sumCA[j + 1] - sumCA[i];
int TA = sumTA[j + 1] - sumTA[i];
int CT = sumCT[j + 1] - sumCT[i];
int TC = sumTC[j + 1] - sumTC[i];
if (AC + AT != CA + TA)
return -1;
if (CA + CT != AC + TC)
return -1;
if (TA + TC != AT + CT)
return -1;
int res = 0;
int ac = min(AC, CA);
res += ac;
AC -= ac;
CA -= ac;
int at = min(AT, TA);
res += at;
AT -= at;
TA -= at;
int ct = min(CT, TC);
res += ct;
CT -= ct;
TC -= ct;
return res + AC + AT + CA + TA;
}
