#include<stdio.h>

int main(){
	int deduction,poll_sum=0,winner_poll=0,athlete_sum,winner_num,poll,i;

	while(1){
		scanf("%d %d %d",&athlete_sum, &winner_num, &deduction);
		poll_sum=0;
		winner_poll=0;
		
		if(athlete_sum==0 && winner_num==0 && deduction==0)break;

		for(i=1;i<=athlete_sum;i++){
			scanf("%d",&poll);
			poll_sum+=poll;
			if(winner_num==i)
				winner_poll=poll;
		}

		printf("%d\n",winner_poll?poll_sum*100*(100-deduction)/100/winner_poll:0);

		}

	return 0;
}