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#include <stdlib.h>
//---===---
#include <stdio.h>
#include <unistd.h>

typedef unsigned int uint;

char buf_in[4096000];
int buf_in_head = 0;
int buf_in_tail = 0;

static int getChar(void) {
  while (buf_in_head == buf_in_tail) {
    int rv = read(0, buf_in, sizeof(buf_in));
    if (rv > 0) {
      buf_in_head = 0;
      buf_in_tail = rv;
      break;
    };
    if (rv == 0) return EOF;
  }
  return buf_in[buf_in_head++];
}

// only 1 call is safe, and only if previously getChar() had been called.
static void ungetChar(void) {
  --buf_in_head;
}

static uint getUInt() {
  uint v;
  int c;
  for (;;) {
    c = getChar();
    if (c < '0') continue;
    if (c > '9') continue;
    v = c - '0';
    break;
  };
  for (;;) {
    c = getChar();
    if (c < '0') break;
    if (c > '9') break;
    v *= 10;
    v += c - '0';
  };
  ungetChar();
  return v;
}
//---===---

#define MAX_NM 200000
#define MAX_K 500000

int n, m; // 0 <= m < n <= 200,000
int k; // 0 <= k <= 500,000

typedef struct {
  int f;
  int g; // 1 <= g[i] <= 1,000,000,000
} tt;

tt Tubes[MAX_NM];

struct rr;

typedef struct rr {
  struct rr * next;
  int c, d; // 0 <= c[i], d[i] < n, c[i] != d[i]
  int idx;
  int tmin, tmax;
} rr;

rr Reactions[MAX_K + 1];

typedef struct {
  int a, b; // 0 <= a[i], b[i] < n, a[i] != b[i]
  rr * queries;
  rr * known;
} mm;

mm Merges[MAX_NM]; // merges

static inline int cmp(const rr * a, const rr * b) {
  if (a->tmin < b->tmin) return -1;
  if (a->tmin > b->tmin) return +1;

  if (a->idx < b->idx) return -1;
  if (a->idx > b->idx) return +1;

  return 0;
}

int void_cmp(const void * a, const void * b) {
  return cmp((const rr*)a, (const rr*)b);
}



int Find(int x) {
  int y = x;

  // Find the ultimate parent
  while (Tubes[y].f >= 0) {
    y = Tubes[y].f;
  };

  // y is now the ultimate parent

  // Update everyone to point at it
  while (Tubes[x].f >= 0) {
    int px = x;
    x = Tubes[x].f;
    Tubes[px].f = y;
  };

  return y;
}

int Union(int x, int y) {
  x = Find(x);
  y = Find(y);
  if (x == y) return 0; // false - no union needed
  if (Tubes[x].f < Tubes[y].f) {
    // x has high rank (stored negative)
    Tubes[y].f = x;
  } else if (Tubes[x].f > Tubes[y].f) {
    // y has has high rank (stored negative)
    Tubes[x].f = y;
  } else { // Tubes[x].f == Tubes[y].f
    // equal ranks
    --Tubes[y].f; // rank increase
    Tubes[x].f = y;
  };
//--Fcnt;
  return 1; // true - non-trivial union performed
}


int main (void) {
  long long v = 0;
  int i;

  // 0 <= m < n <= 200,000
  n = getUInt();
  m = getUInt();

  // 0 <= k <= 500,000
  k = getUInt();

  for (i = 0; i < n; ++i) {
    Tubes[i].g = getUInt(); // 1 <= g[i] <= 1,000,000,000
  };

  // a[i] shows up at most once, and once it does show up, never as b[j] for any j >= i
  for (i = 0; i < m; ++i) {
    Merges[i].a = getUInt() - 1; // 0 <= a[i] < n, a[i] != b[i]
    Merges[i].b = getUInt() - 1; // 0 <= b[i] < n
    Merges[i].queries = NULL;
    Merges[i].known = NULL;
  };

  // unordered pair (c[i], d[i]) shows up at most once
  for (i = 0; i < k; ++i) {
    Reactions[i].next = (i + 1 < k) ? &Reactions[i + 1] : NULL;
    Reactions[i].c = getUInt() - 1; // 0 <= c[i] < n, c[i] != d[i]
    Reactions[i].d = getUInt() - 1; // 0 <= d[i] < n
    Reactions[i].idx = i;
    Reactions[i].tmin = 0;  // Could react in [tmin, tmax), known to have already reacted at tmax
    Reactions[i].tmax = m;
  };

  Merges[(0 + m) / 2].queries = &Reactions[0];

  for (;;) {
    int unknowns = 0;
//printf("tick\n");
    // reset FnU
    for (i = 0; i < n; ++i) Tubes[i].f = -1;

    for (i = 0; i < m; ++i) {
      rr * q = Merges[i].queries;
      Merges[i].queries = NULL;

//printf("%d %d+%d\n", i, Merges[i].a, Merges[i].b);
      Union(Merges[i].a, Merges[i].b);

      while (q) {
        int tmid;
        rr * qnext = q->next;
        q->next = NULL;
        if (Find(q->c) == Find(q->d)) {
          // has already reacted at time 'i'
          q->tmax = tmid = i;
        } else {
          // hasn't reacted at time 'i', could still react at 'i+1'
          q->tmin = tmid = i + 1;
        };
//printf("%d: %d-%d\n", q->idx, q->tmin, q->tmax);
        if (q->tmin == q->tmax) { // and one of them is tmid
          q->next = Merges[tmid].known;
          Merges[tmid].known = q;
        } else {
          ++unknowns;
          tmid = (q->tmin + q->tmax) / 2;
          q->next = Merges[tmid].queries;
          Merges[tmid].queries = q;
        };
        q = qnext;
      };
    };

    if (unknowns == 0) break;
  };

  qsort(Reactions, k, sizeof(rr), void_cmp);

  for (i = 0; i < k; ++i) {
    int c = Reactions[i].c;
    int d = Reactions[i].d;
    //int idx = Reactions[i].idx;
    int tmin = Reactions[i].tmin;
    if (tmin >= m) break;
    //int tmax = Reactions[i].tmax;
    //printf("%d->%d (%d) %d-%d\n", c, d, idx, tmin, tmax);
    if (Tubes[c].g < Tubes[d].g) {
      v += Tubes[c].g;
      Tubes[d].g -= Tubes[c].g;
      Tubes[c].g = 0;
    } else {
      v += Tubes[d].g;
      Tubes[c].g -= Tubes[d].g;
      Tubes[d].g = 0;
    };
  };

  printf("%lld\n", v * 2);

  return 0;
}