（无言）

#include<bits/stdc++.h>
#include<vector>
#include<sstream>
using namespace std;
int main(){
ios_base::sync_with_stdio(false);//万金油
cin.tie(nullptr);//还是万金油
vector<int> n;
string li, to;
getline(cin, li);
stringstream ss(li);
while(getline(ss, to, ',')){
n.push_back(stoi(to));
}
int t;
cin >> t;
int l = 0, r = n.size() - 1, ans = -1;
while(l <= r){
int mid = l + (r - l) / 2;
if(n[mid] == t){
ans = mid;
break;
}else if(n[mid] < t){
l = mid + 1;
}else{
r = mid - 1;
}
}
cout << ans;
return 0;
}