#include <bits/stdc++.h>
#include "dna.h"
#define N 100005
#define wr cout << "Continue debugging\n";
#define ll long long int
#define pii pair <string, int>
#define pb push_back
#define ff first
#define ss second
using namespace std;
int ans;
map <pii, int> pr;
map <string, int> m;
vector <string> v = {"AT", "TA", "AC", "CA", "CT", "TC"};
void calc(){
for (auto s : v){
string c = "";
c += s[1];
c += s[0];
int mn = min(m[s], m[c]);
ans += mn;
m[s] -= mn;
m[c] -= mn;
}
}
void init(string a, string b){
int n = a.size();
a = ' ' + a;
b = ' ' + b;
for (int i = 1; i <= n; i++){
if (a[i] != b[i]){
string s = "";
s += a[i];
s += b[i];
pr[{s, i}] = 1;
}
}
for (int i = 2; i <= n; i++){
for (auto s : v) pr[{s, i}] += pr[{s, i - 1}];
}
}
int get_distance(int l, int r){
for (auto s : v) m[s] = 0;
l++; r++; ans = 0;
for (auto s : v) m[s] = pr[{s, r}] - pr[{s, l - 1}];
calc();
for (auto s : v){
string c = "", t1 = "";
c += s[1];
if ('A' != s[0] and 'A' != s[1]) c += 'A';
else if ('T' != s[0] and 'T' != s[1]) c += 'T';
else c += 'C';
t1 += s[0];
t1 += c[1];
int mn = min(m[s], m[c]);
ans += mn;
m[s] -= mn;
m[c] -= mn;
m[t1] += mn;
}
calc();
for (auto i : v) if (m[i]) return -1;
return ans;
}
// int main ()
// {
// ios::sync_with_stdio(false);
// cin.tie(0);
// int n1, q1;
// string a, b;
// cin >> n1 >> q1 >> a >> b;
// init(a, b);
// while(q1--){
// int x, y;
// cin >> x >> y;
// cout << get_distance(x, y);
// }
// }
