#include<iostream>
#include<cstdlib>
#include<cstdio>
#define ll long long
#include<vector>
using namespace std;
ll n,m,q,a,b,w,s=0;
int main(){
    ios_base::sync_with_stdio(0);
    cin>>n>>m>>q;
    b=-1;
    cin>>a;
    s=a;
    w=a;
    for(int i=1;i<n;i++){
        cin>>a;
        if(a>s){
            w+=a-s;
            s=a;
        }
        s-=a;
        if(i<n-1){
            w+=a;
            s+=a;
        }
        //if(b!=-1) w+=max(a,b);
        //b=a;
    }
    for(int i=0;i<m;i++) cin>>a>>b;
    cout<<w<<"\n";
    return 0;
}