#include<stdio.h>
//#include<time.h>
//#include<stdlib.h>

int main(void){
    //srand(time(NULL));

    int L,R,C,x;
    int oturi,min;
    //int second;

    scanf("%lld %lld %lld",&L,&R,&C);

    min = 999;

    //while(second < 2){
        //second = time(NULL);

        //L = rand();
        //R = rand();
        //C = rand();

        for(x = L;x <= R;x++){
            oturi = ((1000 - ((x*C) % 1000)) % 1000);

            if(oturi < min){
                min = oturi;
            }
        }

        //printf("L:%d R:%d C:%d\n",L,R,C);
        printf("%d\n",min);

        //second = time(NULL) - second;
        //printf("経過時間:%d\n",second);
    
        //printf("\n");
    //}

    return 0;
}