#include <bits/stdc++.h>
int main() {
  int n, x, y, a;
  scanf("%d%d%d", &n, &x, &y);
  a = n * y / 10;
  if (a <= x * 10)
    printf("0\n");
  else
    printf("%d\n", (a - x * 10) / 10 + ((a - x * 10) % 10 ? 1 : 0));
  return 0;
}
