#include <stdio.h>
#include <ctype.h>
#include <string.h>
FILE *f=fopen("next.in","r");
FILE *g=fopen("next.out","w");
long long t,b;
char a[1000000];
long i;

int mod()   
{for(i=0;i<strlen(a)-1;i++) 
      t = (t * 10 +a[i]-'0') % b;   //fprintf(g,"%d ",i);
      return 0;   
}   
int main(){
fgets(a,1000000,f);    
fscanf(f,"%d",&b);
mod();

fprintf(g,"%d",t);
//fprintf(g,"%d",strlen(a));
//fprintf(g,"%d",a[2]-10);
    fclose(f);
    fclose(g);
    return 0;
}