#include "dna.h"
#include<bits/stdc++.h>
using namespace std;
string s1, s2;
void init(std::string a, std::string b) {
s1 = a;s2 = b;
}
int get_distance(int x, int y) {
long long count = 0;
string NewNewS1 = "";
string NewNewS2 = "";
for(int i=x;i<=y;i++){
NewNewS1+=s1[i];
NewNewS2+=s2[i];
}
string NewS1 = NewNewS1;
string NewS2 = NewNewS2;
sort(NewNewS1.begin(),NewNewS1.end());
sort(NewNewS2.begin(),NewNewS2.end());
if(NewNewS1 != NewNewS2){
return -1;
}
else{
for(int i = 0;i < NewS1.size();i++){
if(NewS1[i] != NewS2[i]){
count++;
}
}
return (count+1)/2;
}
return 0;
}
