#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
string a, b;
map<string, int[100000]> prefix;
void init(string a1, string b1) {
a = a1;
b = b1;
int n = a.length();
for (int i = 0; i < n; i++){
prefix["ta"][i+1] = (a[i] == 'T' && b[i] == 'A') ? prefix["ta"][i] + 1 : prefix["ta"][i];
prefix["at"][i+1] = (a[i] == 'A' && b[i] == 'T') ? prefix["at"][i] + 1 : prefix["at"][i];
prefix["tc"][i+1] = (a[i] == 'T' && b[i] == 'C') ? prefix["tc"][i] + 1 : prefix["tc"][i];
prefix["ct"][i+1] = (a[i] == 'C' && b[i] == 'T') ? prefix["ct"][i] + 1 : prefix["ct"][i];
prefix["ac"][i+1] = (a[i] == 'A' && b[i] == 'C') ? prefix["ac"][i] + 1 : prefix["ac"][i];
prefix["ca"][i+1] = (a[i] == 'C' && b[i] == 'A') ? prefix["ca"][i] + 1 : prefix["ca"][i];
}
}
int get_distance(int x, int y) {
x++;
y++;
int ta = prefix["ta"][y] - prefix["ta"][x-1];
int at = prefix["at"][y] - prefix["at"][x-1];
int tc = prefix["tc"][y] - prefix["tc"][x-1];
int ct = prefix["ct"][y] - prefix["ct"][x-1];
int ac = prefix["ac"][y] - prefix["ac"][x-1];
int ca = prefix["ca"][y] - prefix["ca"][x-1];
int ret = 0;
int m = min(ta, at);
ta -= m;
at -= m;
ret += m;
m = min(tc, ct);
tc -= m;
ct -= m;
ret += m;
m = min(ac, ca);
ac -= m;
ca -= m;
ret += m;
if (ta != ac || ta != ct){
return -1;
} else {
ret += 2*ta;
}
if (at != ca || at != tc){
return -1;
} else {
ret += 2*at;
}
return ret;
}
