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import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.PriorityQueue;

public class fio {
	
	static Reaction[] tozero;
	
	static class Reaction implements Comparable<Reaction> {
		int first;
		int second;
		int affects;
		int priority;

		Reaction(int first, int second, int priority) {
			this.first = first;
			this.second = second;
			this.priority = priority;
		}
		
		Reaction sibling;
		Reaction next, previous;

		RList list;
		boolean removed = false;

		void remove() {
			if (this == list.head) list.head = next;
			if (this == list.tail) list.tail = previous;
			if (next != null) next.previous = previous;
			if (previous != null) previous.next = next;
			list.size--;
			
			if (this == tozero[this.first]) tozero[this.first] = next;
		}
		
		@Override
		public int compareTo(Reaction o) {
			return priority - o.priority;
		}
	}
	
	static class RList {
		int size = 0;
		
		Reaction head = null;
		Reaction tail = null;
		
		void add(Reaction r) {
			r.list = this;
			if (size == 0) {
				head = r;
				tail = r;
				
				tozero[r.first] = r;
			} else {
				r.previous = tail;
				tail.next = r;
				tail = r;
			}
			size++;
		}
		
		void append(RList a) {
			if (a.size > 0) {
				if (size == 0) {
					head = a.head;
				} else {
					tail.next = a.head;
					a.head.previous = tail;
				}
				tail = a.tail;
				size += a.size;
			}
		}
	}
	
	public static void main(String[] args) {
		long osad = 0;
		
		int n = R.i();
		int m = R.i();
		int k = R.i();
		
		int[] g = new int[n + 1];
		int[] whereis = new int[n + 1];
		RList[] t = new RList[n + 1];
		for (int i = 1; i <= n; i++) {
			g[i] = R.i();
			whereis[i] = i;
			t[i] = new RList();
		}
		
		int[] f = new int[2 * m];
		for (int i = 0; i < m; i++) {
			f[2 * i] = R.i();
			f[2 * i + 1] = R.i();
		}
		
		int c, d;
		Reaction r1, r2;
		tozero = new Reaction[n + 1];
		for (int i = 0; i < k; i++) {
			c = R.i();
			d = R.i();
			r1 = new Reaction(c, d, i);
			r2 = new Reaction(d, c, i);
			r1.affects = d;
			r2.affects = c;
			r1.sibling = r2;
			r2.sibling = r1;
			
			t[c].add(r1);
			t[d].add(r2);
		}
		
		int a, b, dest;
		int aa, bb;
		int o;
		Reaction r, delr;
		RList ar, br, destr;
		PriorityQueue<Reaction> react = new PriorityQueue<Reaction>(500000);
		for (int i = 0; i < m; i++) {
			aa = f[2 * i];
			bb = f[2 * i + 1];
			
			a = whereis[aa];
			b = whereis[bb];
			
			ar = t[a];
			br = t[b];
			
			react.clear();
			if (ar.size < br.size) {
				r = ar.head;
				br.append(ar);
				destr = br;
				dest = b;
			} else {
				r = br.head;
				ar.append(br);
				destr = ar;
				dest = a;
			}
			
			whereis[bb] = dest;
			
			while (r != null) {
				r.list = destr;
				if (r.affects == dest) {
					react.add(r);
					r.remove();
					r.sibling.remove();
				} else {
					r.sibling.affects = dest;
				}
				r = r.next;
			}
			
			while (!react.isEmpty()) {
				r = react.poll();
				c = r.first;
				d = r.second;
				o = Math.min(g[c], g[d]);
				if (o > 0) {
					osad += 2 * o;
					g[c] -= o;
					g[d] -= o;

					// usuwanie reakcji wyzerowanego
					if (g[c] == 0) {
						delr = tozero[c];
						while (delr != null && delr.first == c) {
							delr.remove();
							delr.sibling.remove();
							delr = delr.next;
						}
					}
					if (g[d] == 0) {
						delr = tozero[d];
						while (delr != null && delr.first == d) {
							delr.remove();
							delr.sibling.remove();
							delr = delr.next;
						}
					}
				}
			}
			
		}
		
		W.l(osad);
		W.flush();
	}
	

	static class R {
		static InputStream is=new BufferedInputStream(System.in);
		static int b='\n';
		static void next(){try{b=is.read();}catch(Exception e){}}
		static void skip(){while(b=='\n'||b==' '||b=='\r'||b=='\t')next();}
		static char c(){skip();char c=(char)b;next();return c;}
		static int i(){skip();int i=0;while(b>='0'&&b<='9'){i=10*i+(b-'0');next();}return i;}
		static long l(){skip();long i=0;while(b>='0'&&b<='9'){i=10*i+(b-'0');next();}return i;}
	}
	static class W {
		static OutputStream os=new BufferedOutputStream(System.out,4096);
		static void b(int b){try{os.write(b);}catch(Exception e){}}
		static void c(char c){b(c);}
		static void cs(char c){c(c);space();}
		static void cn(char c){c(c);newLine();}
		static void i(int i){if(i>9)i(i/10);b('0'+(i%10));}
		static void is(int i){i(i);space();}
		static void in(int i){i(i);newLine();}
		static void l(long l){if(l>9)l(l/10);b('0'+(int)(l%10));}
		static void ls(int l){l(l);space();}
		static void ln(int l){l(l);newLine();}
		static void s(String s){try{os.write(s.getBytes());}catch(Exception e){}}
		static void ss(String s){s(s);space();}
		static void sn(String s){s(s);newLine();}
		static void tn(boolean b){sn(b?"TAK":"NIE");}
		static void space(){b(' ');}
		static void newLine(){b('\n');}
		static void flush(){try{os.flush();}catch(Exception e){}};
	}
	static class T {
		static List<String> s=new ArrayList<String>();
		static List<Long> t=new ArrayList<Long>();
		static void t(String n){s.add(n);t.add(System.currentTimeMillis());}
		static void err(){t.add(System.currentTimeMillis());System.err.println();for(int i=0;i<s.size();i++){System.err.println(s.get(i)+": "+(t.get(i+1)-t.get(i)));}System.err.println("TOTAL: "+(t.get(t.size() - 1)-t.get(0)));System.err.flush();}
	}

}