// AOJ 2018: Princess's Gamble
// 2017.9.30 bal4u@uu

#include <stdio.h>

int main()
{
	int n, m, p, x, i, sum, ans;

	while (scanf("%d%d%d", &n, &m, &p) && n > 0) {
		for (sum = ans = 0, i = 1; i <= n; i++){
			scanf("%d", &x); sum += x;
			if (i == m) ans = x;
		}
		if (ans > 0) ans = sum * (100 - p) / ans;
		printf("%d\n", ans);
	}
	return 0;
}