#include<stdio.h>
#include<algorithm>
#include<string.h>
#include<math.h>
#include<string>
#include<iostream>
#include<queue>
#include<stack>
#include<map>
#include<vector>
#include<set>
using namespace std;
typedef long long LL;
#define mid (L+R)/2
#define lson rt*2,L,mid
#define rson rt*2+1,mid+1,R
#pragma comment(linker, "/STACK:102400000,102400000")
const int maxn = 1e5+300;
const int INF = 0x3f3f3f3f;
typedef long long  LL;
typedef unsigned long long ULL;
LL presum[maxn];
struct Interval{
    int l, r;
}intervals[maxn];
struct Seg{
    int cover;
}segs[maxn*4];
bool cmp(Interval a, Interval b){
    return a.r < b.r;           //
}
void PushUp(int rt){
    segs[rt].cover = segs[rt*2].cover + segs[rt*2+1].cover;
}
void buildtree(int rt,int L,int R){
    if(L == R){
        segs[rt].cover = 0;
        return;
    }
    buildtree(lson);
    buildtree(rson);
    PushUp(rt);
}
void Update(int rt,int L,int R,int id){
    if(L == R){
        segs[rt].cover++;
        return ;
    }
    if(id <= mid){
        Update(lson,id);
    }else{
        Update(rson,id);
    }
    PushUp(rt);
}
int query(int rt,int L, int R,int k){
    if(L == R){
        return L;
    }
    if(k <= segs[rt*2].cover){
        return query(lson,k);
    }else{
        return query(rson,k-segs[rt*2].cover);
    }
}
int main(){
    int n, k, m;
    while(scanf("%d%d%d",&n,&k,&m)!=EOF){
        buildtree(1,1,n);
        LL a;
        for(int i = 1; i <= n; i++){
            scanf("%lld",&a);
            presum[i] = presum[i-1] + a;
        }
        int l, r;
        for(int i = 1; i <= m; i++){
            scanf("%d%d",&l,&r);
            intervals[i].l = l;
            intervals[i].r = r;
        }
        sort(intervals+1,intervals+1+m,cmp);
        for(int i = m-k+1; i <= m; i++){
            Update(1,1,n,intervals[i].l);
        }
        LL ans = 0;
        for(int i = m-k+1; i >= 1; i--){
            int l = query(1,1,n,k);
            if(l <= intervals[i].r){
                ans = max(ans, presum[intervals[i].r] - presum[l-1]);
            }
            Update(1,1,n,intervals[i-1].l);
        }
        printf("%lld\n",ans);
    }
    return 0;
}

/*
5 1 1
1 2 3 4 6
4 5

3 4


*/