#include <stdio.h>

int main()
{
	long long int ans = 12345;
	long long int a,b,c;
	scanf("%lld%lld%lld",&a,&b,&c);
	for(long long int i=a;i<=b&&i<=a+1000;i++)
	{
		long long int val = (i*c)%1000;
		val = (1000-val)%1000;
		ans = ans<val?ans:val;
	}
	printf("%lld",ans);
}