#include <bits/stdc++.h>
#define sz(x) (int)x.size()
#define int long long
using namespace std;
using ll = long long;
string a, b;
int n;
bool sub3 = 1;
vector<vector<int> > prefixA, prefixT, prefixC;
vector<int> prefixAT, prefixAC, prefixCT;
void init(string x, string y) {
a = x;
b = y;
n = sz(a);
for(char &ch : a) sub3 = sub3 && (ch == 'C');
for(char &ch : b) sub3 = sub3 && (ch == 'C');
prefixA.resize(2, vector<int>(n+1, 0));
prefixT.resize(2, vector<int>(n+1, 0));
prefixC.resize(2, vector<int>(n+1, 0));
prefixAT.resize(n+1, 0);
prefixCT.resize(n+1, 0);
prefixAC.resize(n+1, 0);
for(int i=0; i<n; i++) {
prefixAT[i+1] = prefixAT[i] + (a[i] != b[i] && ((a[i] == 'A' && b[i] == 'T') || (a[i] == 'T' && b[i] == 'A')));
prefixCT[i+1] = prefixCT[i] + (a[i] != b[i] && ((a[i] == 'C' && b[i] == 'T') || (a[i] == 'T' && b[i] == 'C')));
prefixAC[i+1] = prefixAC[i] + (a[i] != b[i] && ((a[i] == 'A' && b[i] == 'C') || (a[i] == 'C' && b[i] == 'A')));
prefixA[0][i+1] = prefixA[0][i] + (a[i] == 'A');
prefixA[1][i+1] = prefixA[1][i] + (b[i] == 'A');
prefixT[0][i+1] = prefixT[0][i] + (a[i] == 'T');
prefixT[1][i+1] = prefixT[1][i] + (b[i] == 'T');
prefixC[0][i+1] = prefixC[0][i] + (a[i] == 'C');
prefixC[1][i+1] = prefixC[1][i] + (b[i] == 'C');
}
}
int32_t get_distance(int32_t x, int32_t y) {
if(y - x <= 100000) {
if(prefixA[0][y+1] - prefixA[0][x] != prefixA[1][y+1] - prefixA[1][x]) return -1;
if(prefixT[0][y+1] - prefixT[0][x] != prefixT[1][y+1] - prefixT[1][x]) return -1;
if(prefixC[0][y+1] - prefixC[0][x] != prefixC[1][y+1] - prefixC[1][x]) return -1;
return (prefixAT[y+1] + prefixAC[y+1] + prefixCT[y+1] - prefixAT[x] - prefixAC[x] - prefixCT[x] + 1) / 2;
}
return 0;
}
// int32_t main() {
// int n, q;
// cin >> n >> q;
// string x, y;
// cin >> x >> y;
// init(x, y);
// while(q--) {
// int l, r;
// cin >> l >> r;
// cout << get_distance(l, r) << '\n';
// }
// return 0;
// }
