#include <bits/stdc++.h>
using namespace std;
typedef string str;
typedef vector<int> vi;
str a, b;
vi ac, at, ca, ct, ta, tc, as1, cs1, ts1, as2, cs2, ts2;
void init(str a1, str b1)
{
a = a1;
b = b1;
int n = a.length();
ac = vi(n);
at = vi(n);
ca = vi(n);
at = vi(n);
ta = vi(n);
tc = vi(n);
for (int i = 0; i < n; i++)
{
switch (b[i])
{
case 'A':
as2[i] = i == 0 ? 1 : as2[i - 1] + 1;
cs2[i] = i == 0 ? 0 : cs2[i - 1];
ts2[i] = i == 0 ? 0 : ts2[i - 1];
break;
case 'C':
as2[i] = i == 0 ? 0 : as2[i - 1];
cs2[i] = i == 0 ? 1 : cs2[i - 1] + 1;
ts2[i] = i == 0 ? 0 : ts2[i - 1];
break;
case 'T':
as2[i] = i == 0 ? 0 : as2[i - 1];
cs2[i] = i == 0 ? 0 : cs2[i - 1];
ts2[i] = i == 0 ? 1 : ts2[i - 1] + 1;
break;
}
switch (a[i])
{
case 'A':
as1[i] = i == 0 ? 1 : as1[i - 1] + 1;
cs1[i] = i == 0 ? 0 : cs1[i - 1];
ts1[i] = i == 0 ? 0 : ts1[i - 1];
if (b[i] == 'C')
ac[i] = i == 0 ? 1 : ac[i - 1] + 1;
else
ac[i] = i == 0 ? 0 : ac[i - 1];
if (b[i] == 'T')
at[i] = i == 0 ? 1 : at[i - 1] + 1;
else
at[i] = i == 0 ? 0 : at[i - 1];
break;
case 'C':
as1[i] = i == 0 ? 0 : as1[i - 1];
cs1[i] = i == 0 ? 1 : cs1[i - 1] + 1;
ts1[i] = i == 0 ? 0 : ts1[i - 1];
if (b[i] == 'A')
ca[i] = i == 0 ? 1 : ca[i - 1] + 1;
else
ca[i] = i == 0 ? 0 : ca[i - 1];
if (b[i] == 'T')
ct[i] = i == 0 ? 1 : ct[i - 1] + 1;
else
ct[i] = i == 0 ? 0 : ct[i - 1];
break;
case 'T':
as1[i] = i == 0 ? 0 : as1[i - 1];
cs1[i] = i == 0 ? 0 : cs1[i - 1];
ts1[i] = i == 0 ? 1 : ts1[i - 1] + 1;
if (b[i] == 'C')
tc[i] = i == 0 ? 1 : tc[i - 1] + 1;
else
tc[i] = i == 0 ? 0 : tc[i - 1];
if (b[i] == 'A')
ta[i] = i == 0 ? 1 : ta[i - 1] + 1;
else
ta[i] = i == 0 ? 0 : ta[i - 1];
break;
}
}
}
int get_distance(int x, int y)
{
if (
(as1[y] - (x == 0 ? 0 : as1[x - 1])) != (as2[y] - (x == 0 ? 0 : as2[x - 1])) ||
(cs1[y] - (x == 0 ? 0 : cs1[x - 1])) != (cs2[y] - (x == 0 ? 0 : cs2[x - 1])) ||
(ts1[y] - (x == 0 ? 0 : ts1[x - 1])) != (ts2[y] - (x == 0 ? 0 : ts2[x - 1])))
return -1;
int cntAC = ac[y] - (x == 0 ? 0 : ac[x - 1]);
int cntAT = at[y] - (x == 0 ? 0 : at[x - 1]);
int cntCA = ca[y] - (x == 0 ? 0 : ca[x - 1]);
int cntCT = ct[y] - (x == 0 ? 0 : ct[x - 1]);
int cntTA = ta[y] - (x == 0 ? 0 : ta[x - 1]);
int cntTC = tc[y] - (x == 0 ? 0 : tc[x - 1]);
int c = 0, m = cntAC + cntCA + cntAT + cntTA + cntTC + cntTC;
m -= min(cntAC, cntCA) * 2;
c += min(cntAC, cntCA);
m -= min(cntAT, cntTA) * 2;
c += min(cntAT, cntTA);
m -= min(cntTC, cntCT) * 2;
c += min(cntTA, cntCT);
return m / 3 * 2 + c;
}
