/*扩展欧几里得 ax%b==1  -> ax-by==1 求不定方程的一组解 使x为最小正整数解 */#include
     
      #include
      
       #include
       
        using namespace std;int x,y,gcd;int Extend(int a,int b){    if(b==0)      {          x=1;y=0;          gcd=a;      }    else       {          Extend(b,a%b);          int tmp=x;          x=y;          y=tmp-a/b*y;      }}int main(){    int a,b;    scanf("%d%d",&a,&b);    Extend(a,-b);    x=x*(1/gcd);    if(x<0)while(x<0)x=x+b;    else while(x-b>0)x=x-b;    printf("%d\n",x);    return 0;}