//
// main.cpp
//
// Created by Panagiotis Chadjicostas on
// Copyright © Panagiotis Hadjicostas. All rights reserved.
//
#include <iostream>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <fstream>
#include <iomanip>
#include <iterator>
#include <limits>
#include <list>
#include <cstring>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#include <unordered_map>
using namespace std;
typedef long long ll;
typedef vector<ll> vi;
typedef pair<ll,ll> ii;
#define fo(i,a,b) for(int i = a; i<=b; i++)
#define f(i,b) for(int i=0;i<b;i++)
#define F first
#define S second
#define sz size
#define ls s,m,idx<<1
#define rs m+1,e,idx<<1|1
const ll MOD=ll(1e9)+7;
const ll MAXN=2*ll(1e6);
void checker(){
ll n=rand()%20+2;
vi a(n,ll());
for(ll i=0;i<n;i++){
a[i]=rand()%20+2;
}
for(ll b=0;b<(1<<n);b++){
vi on,off;
for(ll i=0;i<n;i++){
if(i&(1<<i)){
on.push_back(i);
}
else{
off.push_back(i);
}
}
}
}
///////////////////////////////////////////////////////////////////////
vector<ll> pa,pb,pab;
void init(string a, string b){
ll n=a.size();
pa.assign(n+1,0);
pb.assign(n+1,0);
pab.assign(n+1,0);
a='1'+a;
b='1'+b;
for(ll i=1;i<=n;i++){
pa[i]=pa[i-1]+a[i]=='A';
pb[i]=pb[i-1]+b[i]=='A';
pab[i]=pab[i-1]+a[i]!=b[i];
}
}
int get_distance(int x, int y){
x--;
y--;
if(pa[y]-pa[x-1]!=pb[y]-pb[x-1]){
return -1;
}
else{
return pab[y]-pab[x-1];
}
}
