#include<bits/stdc++.h>
using namespace std;
extern "C" int Seniorious(int);
extern "C" int Chthollly(int n)
{
    int ans=1;
    int l=1,r=n;
    while(l<r)
    {
        int mid=(l+r)>>1;
        int res=Seniorious(mid);
        if(res==1) r=mid-1;
        else if(res==-1) l=mid+1;
        else return mid;
    }
}