#include<bits/stdc++.h>
using namespace std;
#define task "task"
#define ii pair<int,int>
#define fi first
#define se second
//#define int long long
#define ll long long
#define ld double
#define mp make_pair
#define lg2 30
#define iii pair<int,ii>
#define iiii pair<ii,ii>
#define base 29
#define eps 1e-8
int dx[]= {0LL,0LL,1,-1,1,1,-1,-1};
int dy[]= {1,-1,0LL,0LL,1,-1,1,-1};
const int maxn=4e5+1;
const int mod=1e9+7;
int n,k,r,a[maxn],vis[maxn];
vector<int>e[maxn];
void init()
{
    cin>>n>>k>>r;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    vector<ii>vec;
    for(int i=1;i<=r;i++)
    {
        int b,q;
        cin>>b>>q;
        vis[b]=max(b,q);
    }
    int ans=n+1;
    multiset<int>s;
    bool ok=false;
    for(int i=1;i<=n;i++)
    {
        if(vis[a[i]])
        {
            if(e[a[i]].size()>=vis[a[i]])
            {
                s.erase(s.find(e[a[i]][e[a[i]].size()-vis[a[i]]]));
            }
        }
        e[a[i]].push_back(i);
        if(vis[a[i]])
        {
            if(e[a[i]].size()>=vis[a[i]])
            {
                s.insert(e[a[i]][e[a[i]].size()-vis[a[i]]]);
            }
        }
        if(!ok)ok=s.size()==r;
        if(ok)ans=min(ans,i-*s.begin()+1);
    }
    if(ans==n+1)cout<<"impossible";
    else cout<<ans;
}
void process()
{
}
signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if(fopen(task".inp","r"))
    {
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    init();
    process();
    cerr <<endl<< "TIME : " << clock() * 0.001 << "s" << endl ;
}
Compilation message (stderr)
dna.cpp: In function 'int main()':
dna.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
dna.cpp:74:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~| # | Verdict | Execution time | Memory | Grader output | 
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