#include "dna.h"
#include <bits/stdc++.h>
#define bupol __builtin_popcount
#define ll long long
#define ld long double
#define fi first
#define se second
#define pb push_back
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
using namespace std;
const int MAXN = 3e5+10;
const int MAXK = 205;
const int LOG = 20;
const int MOD = 1e9+9;
const int SQRT = 520;
const int INF = 1e9+10;
typedef pair<ll,ll> pii;
typedef pair<int, pii> ipii;
string s, t;
int num[4][4], n;
void init(string a, string b) {
a = '.'+a; b = '.'+b; n = a.size()-1; s = a; t = b;
// for(int i=1; i<=n; i++){
// for(int j=1; j<=3; j++){
// pa[i][j] = pa[i-1][j]; pb[i][j] = pb[i-1][j];
// }
// if(a[i]=='A') pa[i][1]++;
// else if(a[i]=='C') pa[i][2]++;
// else pa[i][3]++;
// if(b[i]=='A')pb[i][1]++;
// else if(b[i]=='C') pb[i][2]++;
// else pb[i][3]++;
// }
}
int at,ta,tc,ct,ac,ca;
int get_distance(int x, int y) {
x++; y++;
for(int i=x; i<=y; i++){
if(s[i]==t[i]) continue;
if(s[i]=='A'){
if(t[i]=='C') ac++;
else at++;
} else if(s[i]=='C'){
if(t[i]=='A') ca++;
else ct++;
} else {
if(t[i]=='A') ta++;
else tc++;
}
}
//cout<<ca<<' '<<ac<<' '<<at<<' '<<ta<<' '<< ct<<' '<< tc << " p\n";
int ans = 0;
int te = min(ac,ca); ans += te;
ac -= te; ca -= te;
te = min(at, ta); ans += te;
at -= te; ta -= te;
te = min(ct, tc); ans += te;
ct -= te; tc -= te;
te = min(min(ca, at), tc); ans += 2*te;
ca -= te; at -= te; tc -= te;
te = min(min(ac, ct), ta); ans += 2*te;
ac -= te; ct -= te; ta -= te;
te = min(ac,ca); ans += te;
ac -= te; ca -= te;
te = min(at, ta); ans += te;
at -= te; ta -= te;
te = min(ct, tc); ans += te;
ct -= te; tc -= te;
if(ac!=0||ca!=0||at!=0||ta!=0||ct!=0||tc!=0) return -1;
return ans;
}
