#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
#define MAXI (int)1e5
#define pb(x) push_back(x)
int s1[(int)1e5+5];
int s2[(int)1e5+5];
int mp(char c){
if(c == 'A') return 0;
if(c == 'T') return 1;
return 2;
}
void init(string x,string y){
for(int i = 0;i<(int)x.length();i++) s1[i] = mp(x[i]);
for(int i = 0;i<(int)y.length();i++) s2[i] = mp(y[i]);
}
int get_distance(int x,int y){
map<int,int> m1,m2;
m1.insert({0,0}); // A
m2.insert({0,0});
m1.insert({1,0}); //T
m2.insert({1,0});
m1.insert({2,0}); // C
m2.insert({2,0});
ll cntr = 1;
for(int i =x;i<=y;i++){
m1[s1[i]]++;
m2[s2[i]]++;
if(s1[i] != s2[i]) cntr++;
}
if(m1[0] != m2[0] || m1[1] != m2[1] || m1[2] != m2[2]) return -1;
return cntr >> 1;
}
