#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define int long long
#define all(a) a.begin(),a.end()
#define pb push_back
const int mod = 1e9 + 7;
const int maxn = 2e5 + 5;
const int lg = 30 ;
void solve(){
int n,k,q;
cin>>n>>k>>q;
int q2 = q;
vector <int> a(n);
for(int& i : a)cin>>i;
vector <int> nm(maxn, 0);
vector <bool> vis(maxn, 0);
while(q2--){
int b,c;
cin>>b>>c;
nm[b] = c;
vis[b] = 1;
}
int mn = 1e9,cnt = 0;
int st = 1,en = n,mid;
while(st <= en){
mid = (st + en)/2;
deque <int> tem;
vector <int> nm2(maxn,0);
bool pos = 0;
vector <bool> vis2;
vis2 = vis;
cnt = 0;
for(int i = 0;i < mid;i++){
if(i < mid)tem.push_back(a[i]);
nm2[a[i]]++;
if(nm2[a[i]] >= nm[a[i]] && vis2[a[i]]){
cnt++;
vis2[a[i]] = 0;
}
if(cnt == q)pos = 1;
}
for(int i = mid;i < n;i++){
if(nm2[tem.front()] == nm[tem.front()])cnt--;
nm2[tem.front()]--;
tem.pop_front();
tem.push_back(a[i]);
nm2[tem.back()]++;
if(nm2[tem.back()] == nm[tem.back()]){
cnt++;
}
if(cnt == q){
pos = 1;
break;
}
}
if(pos){
en = mid - 1;
mn = min(mn, mid);
}
else{
st = mid + 1;
}
}
if(mn == 1e9)cout<<"impossible";
else cout<<mn;
cout<<'\n';
}
signed main(){
cin.tie(0) -> sync_with_stdio(0);
int qu;
qu = 1;
while(qu--){
solve();
}
return 0;
}
