#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize ("unroll-loops,Ofast,O3")
#pragma GCC target("avx,avx2,fma")
#define F first
#define S second
#define sz(x) (int)x.size()
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define NFS ios_base::sync_with_stdio(0) , cin.tie(0) , cout.tie(0) ;
#define file(s) if (fopen(s".in", "r")) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
typedef long long ll;
//random_device(rd);
//mt19937 rng(rd());
//const long long FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
//template<class T> T randomize(T mod){
// return (uniform_int_distribution<T>(0, mod))(rng);
//}
const int E = 1e6+777;
const long long inf = 1e18+777;
const int N = 2e5+777;
const int MOD = 1e9+7;
const bool I = 0;
int n, k, r, a[N], need[N], have[N], sum;
int main(){const auto solve=[&]() -> void{
cin >> n >> k >> r;
for(int i = 1; i <= n; ++i){
cin >> a[i];
}
for(int i = 0; i < r; ++i){
int id, val;
cin >> id >> val;
need[id] = val;
}
int R = 0, res = INT_MAX;
for(int L = 1; L <= n; ++L){
while(R < L - 1){
if(need[a[R]] == have[a[R]]){
--sum;
}
--have[R];
++R;
}
while(sum < r && R + 1 <= n){
++R;
++have[a[R]];
if(need[a[R]] == have[a[R]]){
++sum;
}
// cerr << "R: " << R << " have["<<a[R]<<"]: " << have[a[R]] << " sum: " << sum << '\n';
}
if(sum == r)
res = min(res, R - L + 1);
cerr << "L: " << L << " R: " << R << " sum: " << sum << '\n';
if(need[a[L]] == have[a[L]]){
--sum;
}
--have[a[L]];
}
if(res == INT_MAX) cout << "impossible";
else cout << res;
};NFS;int T=1;if(I)cin>>T;while(T--)solve();}
