#include<stdio.h>
#define M 100

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

  while(1){
    scanf("%d %d %d", &n, &m, &p);
    if(n == 0 && m == 0 && p == 0) break;

    for(i=0, sum=0; i<n; i++){
      scanf("%d", &a);
      sum += a;
      if(i == m-1) x = a;
    }

    if(x == 0){
      printf("0\n");
    }else{
      ans = sum * (M-p) /x;
      printf("%d\n", ans);
    }
  }
  return 0;
}