#include<stdio.h>


int main(){

  int n, m, p, x, sum, k, i;

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

    if(k==0) printf("0\n");
    else printf("%d\n", sum/k);
  }

  return 0;
}