#include <stdio.h>

int main () {
  int l = 0;
  int r = 0;
  int c = 0;
  
  int res = 0;
  
  int ans = 999;
  
  res = scanf("%d", &l);
  res = scanf("%d", &r);
  res = scanf("%d", &c);
  
  for (int i = 0; i < 1000; i++) {
    if (l+i <= r) {
      int tmp = (1000-(((l+i)%1000)*(c%1000))%1000)%1000;
      if (tmp < ans) {
        ans = tmp;
      }
    }
  }
  
  printf("%d\n", ans);
  return 0;
}