#include<bits/stdc++.h>
using namespace std;
using ll = long long int;
vector<ll> X(200000,0),Y(200000,0),Z(200000,0);
void init(string a, string b){
ll N = (ll)a.size();
for(ll i = 0;i < N;i++){
X[i + 1] = X[i];
if(a[i] == b[i]){
X[i + 1]++;
}
Y[i + 1] = Y[i];
Z[i + 1] = Z[i];
if(a[i] == 'A') Y[i + 1] = (Y[i + 1] + 12345678) % 998244353;
if(a[i] == 'T') Y[i + 1] = (Y[i + 1] + 87654321) % 998244353;
if(a[i] == 'C') Y[i + 1] = (Y[i + 1] + 14725836) % 998244353;
if(b[i] == 'A') Z[i + 1] = (Z[i + 1] + 12345678) % 998244353;
if(b[i] == 'T') Z[i + 1] = (Z[i + 1] + 87654321) % 998244353;
if(b[i] == 'C') Z[i + 1] = (Z[i + 1] + 14725836) % 998244353;
}
}
int get_distance(int x, int y){
x--;
if(Y[y] - Y[x] != Z[y] - Z[x]) return -1;
ll ans = (1 + (y - x - (X[y] - X[x]))) / 2;
return ans;
}
