#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define debug(x) cerr << '\n' << __LINE__ << ": " << (#x) << " is " << (x) << endl;
//#define cerr if(false) cerr
const int mxN = 1e6 + 5;
ll n,R1[mxN];
pair<ll,ll> a[mxN];
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n;
for(int i = 1; i <= n; i++){
cin >> a[i].first >> a[i].second;
R1[i] = max(R1[i - 1], a[i].second);
}
ll q;
cin >> q;
ll x;
cin >> x;
ll res = 0;
while(x < n){
if(R1[x] <= x){
res = -1;
break;
}
x = R1[x];
res++;
}
cout << res << '\n';
}
