#include "dna.h"
#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 1e5 + 100, M = 4096 + 10, len = 21, inf = 1e18;
const ll mod = 1e9 + 7;
string a, b;
int n;
void init(string ax, string bx) {
a = ax;
b = bx;
n = (int)a.size();
}
vector <int> vec[6];
int get_distance(int x, int y) {
int ans = 0;
for(int i = x, code; i <= y; i++){
if(a[i] == b[i]) continue;
if(a[i] == 'A'){
if(b[i] == 'C') code = 2;
else code = 0;
}
if(a[i] == 'T'){
if(b[i] == 'A') code = 1;
else code = 4;
}
if(a[i] == 'C'){
if(b[i] == 'A') code = 3;
else code = 5;
}
vec[code].pb(i);
}
bool can = true;
for(int i = 0; i <= 4; i += 2){
if((int)vec[i].size() != (int)vec[i + 1].size()) can = false;
ans += (int)vec[i].size();
}
for(int i = 0; i <= 5; i++){
vec[i].clear();
}
if(can) return ans;
else return -1;
}
// int main(){
// ios::sync_with_stdio(false);
// cin.tie(NULL);
// string ax, bx;
// cin >> ax >> bx;
// init(ax, bx);
// cout << get_distance(3, 5);
// return 0;
// }
