#include <iostream>
#include <vector>
using namespace std;
long long n;
vector <long long> a1, a2, t1, t2, c1, c2, f;
void init(string a, string b){
n = a.size();
a1.resize(n+1); a2.resize(n+1); t1.resize(n+1); t2.resize(n+1); c1.resize(n+1); c2.resize(n+1); f.resize(n+1);
a1[0] = 0; a2[0] = 0; t1[0] = 0; t2[0] = 0; c1[0] = 0; c2[0] = 0; f[0] = 0;
for (long long i = 0; i < n; i++){
a1[i+1] = a1[i]; a2[i+1] = a2[i]; t1[i+1] = t1[i]; t2[i+1] = t2[i]; c1[i+1] = c1[i]; c2[i+1] = c2[i]; f[i+1] = f[i];
if (a[i] == 'A')a1[i+1]++;
else if (a[i] == 'T')t1[i+1]++;
else c1[i+1]++;
if (b[i] == 'A')a2[i+1]++;
else if (b[i] == 'T')t2[i+1]++;
else c2[i+1]++;
if (a[i] != b[i])f[i+1]++;
}
}
int get_distance(int x, int y){
if (((a1[y+1]-a1[x])==(a2[y+1]-a2[x])) && ((t1[y+1]-t1[x])==(t2[y+1]-t2[x])) && ((c1[y+1]-c1[x])==(c2[y+1]-c2[x]))){
long long h = f[y+1]-f[x];
return ((h+h%2)/2);
}
else return -1;
}
