#include<stdio.h>
int main()
{
  int N,M,P,i,sum,sum1=0;
  int X[1000];

  while(1){
    scanf("%d%d%d",&N,&M,&P);
    if(N==0&&M==0&&P==0)break;
    sum=0;sum1=0;
    for(i=0;i<N;i++){
      scanf("%d",&X[i]);
      sum+=X[i]*100;
    }
    sum1=sum;
    sum1*=P;
    sum1/=100;
    sum-=sum1;

    if(X[M-1]!=0)printf("%d\n",sum/X[M-1]);
    else printf("0\n");
  }
  return 0;
}