Problem:
Score : 200 points

Problem Statement

You are visiting a large electronics store to buy a refrigerator and a microwave.

The store sells A kinds of refrigerators and B kinds of microwaves. The i-th refrigerator ( 1 \le i \le A ) is sold at a_i yen (the currency of Japan), and the j-th microwave ( 1 \le j \le B ) is sold at b_j yen.

You have M discount tickets. With the i-th ticket ( 1 \le i \le M ), you can get a discount of c_i yen from the total price when buying the x_i-th refrigerator and the y_i-th microwave together. Only one ticket can be used at a time.

You are planning to buy one refrigerator and one microwave. Find the minimum amount of money required.

Constraints

All values in input are integers.

1 \le A \le 10^5

1 \le B \le 10^5

1 \le M \le 10^5

1 \le a_i , b_i , c_i \le 10^5

1 \le x_i \le A

1 \le y_i \le B

c_i \le a_{x_i} + b_{y_i}

Input

Input is given from Standard Input in the following format:

A B M
a_1 a_2 ... a_A
b_1 b_2 ... b_B
x_1 y_1 c_1
\vdots
x_M y_M c_M

Output

Print the answer.

Sample Input 1

2 3 1
3 3
3 3 3
1 2 1

Sample Output 1

5

With the ticket, you can get the 1-st refrigerator and the 2-nd microwave for 3+3-1=5 yen.

Sample Input 2

1 1 2
10
10
1 1 5
1 1 10

Sample Output 2

10

Note that you cannot use more than one ticket at a time.

Sample Input 3

2 2 1
3 5
3 5
2 2 2

Sample Output 3

6

You can get the 1-st refrigerator and the 1-st microwave for 6 yen, which is the minimum amount to pay in this case.
Note that using a ticket is optional.

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>

int desc(const void *a, const void *b) {
  unsigned long *A = (unsigned long *)a;
  unsigned long *B = (unsigned long *)b;
  
  if (*A > *B) return 1;
  if (*A < *B) return -1;
  return 0;
}

/*
int main() {
  int a[] = {2, 3, 1};
  qsort(a, sizeof(a) / sizeof(*a), sizeof(*a), desc);
  printf("%d%d%d", a[0], a[1], a[2]); // "321"
}
*/

int main (void)
{
  unsigned long a[100010], b[100010], c, x, y;

  unsigned long an, bn, mn, min=300000, i;

  scanf("%lu %lu %lu", &an, &bn, &mn);

  for (i=0; i<an; i++) {
    scanf("%lu", &(a[i]));
  }

  for (i=0; i<bn; i++) {
    scanf("%lu", &(b[i]));
  }

  for (i=0; i<mn; i++) {
    scanf("%lu %lu %lu", &x, &y, &c);
    if (min >= a[x-1] + b[y-1] - c) {
      min = a[x-1] + b[y-1] - c;
    }
  }
  
  qsort(a, an, sizeof(unsigned long), desc);
  qsort(b, bn, sizeof(unsigned long), desc);

  if (min >= a[0] + b[0]) {
    printf("%lu", a[0] + b[0]);
  } else {
    printf("%lu", min);
  }
  
  return 0;
  
}