UVa 11679 - Sub- prime (check if after simulation all banks have >=0 reserve )

Link:https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=78&page=show_problem&problem=2726
Sol:

#include <cstdio>
	int main()
	{
	int B, N, owe, owed, amount;
	int owes[20];
	scanf("%d %d", &B, &N);
	while (B)
	{
	// sets up how much they have in credit or whatever
	for (int i = 0; i < B; ++i)
	scanf("%d", &owes[i]);
	while (N--)
	{
	scanf("%d %d %d", &owe, &owed, &amount);
	owes[owe - 1] -= amount;
	owes[owed - 1] += amount;
	}
	bool positive(true);
	for (int i = 0; i < B; ++i)
	if (owes[i] < 0)
	positive = false;
	if (positive)
	printf("S\n");
	else
	printf("N\n");
	scanf("%d %d", &B, &N);
	}
	}