#include <iostream>
using namespace std;
int N,A,B,cnt=1;
int main()
{
cin>>N>>A>>B;
if(A%2==1) A++;
if(B%2==1) B++;
if(A==B)
{
cout<<1;
return 0;
}
while(N>0)
{
N/=2;
if(A%2==1) A++;
if(B%2==1) B++;
if(A==B) break;
else
{
A/=2;
B/=2;
}
cnt++;
}
if(cnt==1)cout<<-1;
else cout<<cnt;
}