#include <bits/stdc++.h>
inline long long read() {
  char c = getchar();
  while (c != '-' && (c < '0' || c > '9')) c = getchar();
  long long k = 0, kk = 1;
  if (c == '-') c = getchar(), kk = -1;
  while (c >= '0' && c <= '9') k = k * 10 + c - '0', c = getchar();
  return kk * k;
}
using namespace std;
void write(long long x) {
  if (x < 0) x = -x, putchar('-');
  if (x) write(x / 10), putchar(x % 10 + '0');
}
void writeln(long long x) {
  write(x);
  if (x == 0) putchar('0');
  puts("");
}
long long n, m, q, x[2000000], y[2000000], sum[2000000], dd, ff[2000000],
    last[2000000], ans, mi[2000000];
struct lsg {
  long long x, y, z;
} a[2000000];
void build(long long l, long long r, long long d) {
  if (l == r) {
    sum[d] = y[l];
    return;
  }
  long long m = (l + r) / 2;
  build(l, m, d * 2);
  build(m + 1, r, d * 2 + 1);
  sum[d] = sum[d * 2] + sum[d * 2 + 1];
}
long long findit(long long x, long long y, long long l, long long r,
                 long long d) {
  if (!y || !sum[d]) return 0;
  if (sum[d] <= y && x >= r) {
    long long kk = sum[d];
    sum[d] = 0;
    return kk;
  }
  if (l == r) {
    sum[d] -= y;
    return y;
  }
  long long m = (l + r) / 2, dd = 0;
  if (m < x) dd = findit(x, y, m + 1, r, d * 2 + 1);
  if (y > dd) dd += findit(x, y - dd, l, m, d * 2);
  sum[d] = sum[d * 2] + sum[d * 2 + 1];
  return dd;
}
inline bool pd(lsg x, lsg y) { return x.x < y.x || x.x == y.x && x.y < y.y; }
void put(long long x, long long y, long long l, long long r, long long d) {
  if (l == r) {
    mi[d] = y;
    return;
  }
  long long m = (l + r) / 2;
  if (x <= m)
    put(x, y, l, m, d * 2);
  else
    put(x, y, m + 1, r, d * 2 + 1);
  mi[d] = (mi[d * 2] < mi[d * 2 + 1] ? mi[d * 2] : mi[d * 2 + 1]);
}
signed main() {
  n = read();
  m = read();
  q = read();
  for (long long i = 1; i < n; i++) x[i] = read(), y[i] = read();
  for (long long i = n - 2; i >= 1; i--)
    y[i] = (y[i + 1] < y[i] ? y[i + 1] : y[i]), y[i + 1] -= y[i];
  y[n] = 1e9;
  build(1, n, 1);
  for (long long i = 1; i <= m; i++)
    a[i].x = read(), a[i].y = read(), a[i].z = read();
  sort(a + 1, a + 1 + m, pd);
  for (long long i = m; i >= 1; i--) last[a[i].x] = i;
  for (long long k = 1; k <= n; k++) {
    for (long long i = last[k]; a[i].x == k; i++) {
      long long kk = findit(a[i].y, a[i].z, 1, n, 1);
      ff[k] += kk;
    }
  }
  for (long long i = n; i >= 1; i--) ff[i] += ff[i + 1];
  for (long long i = 1; i <= n; i++) x[i] -= ff[i + 1], put(i, x[i], 1, n, 1);
  writeln(ff[1] + mi[1]);
  for (long long i = 1; i <= q; i++) {
    dd = read();
    x[dd] = read() - ff[dd + 1];
    put(dd, x[dd], 1, n, 1);
    writeln(ff[1] + mi[1]);
  }
}
