#include <stdio.h>

int main(){
  int m,t,s;
  int left;
  scanf("%d %d %d",&m,&t,&s);
  if(t!=0){
    double eaten = s / (t*1.0);
    left = (int)(m-eaten);
  }else
    left = 0;
  printf("%d",left);

  return 0;
}