program p1071;
var x,y,z,s,i:longint;
    out:boolean;
procedure check(p:longint);
var x1,y1,temp,i:longint;
    c:array[1..1000] of longint;
begin
     x1:=x;y1:=y;z:=0;
     fillchar(c,sizeof(c),0);
     repeat
           inc(z);
           c[z]:=x1 mod p;
           x1:=x1 div p;
     until x1=0;
     repeat
           temp:=y1 mod p;
           for i:=1 to z+1 do if c[i]=temp then
           begin
                c[i]:=-1;
                break;
           end;
           if i=z+1 then exit;
           y1:=y1 div p;
     until y1=0;
     out:=true;
end;
begin
     readln(x,y);z:=0;out:=false;
     for i:=2 to x do
         if x mod i=y mod i then
         begin
              check(i);
              if out then break;
         end;
     if out then writeln(i)
            else writeln('No solution');
     readln;
end.

> program p1071;
> var x,y,z,s,i:longint;
>     out:boolean;
> procedure check(p:longint);
> var x1,y1,temp,i:longint;
>     c:array[1..1000] of longint;
> begin
>      x1:=x;y1:=y;z:=0;
>      fillchar(c,sizeof(c),0);
>      repeat
>            inc(z);
>            c[z]:=x1 mod p;
>            x1:=x1 div p;
>      until x1=0;
>      repeat
>            temp:=y1 mod p;
>            for i:=1 to z+1 do if c[i]=temp then
>            begin
>                 c[i]:=-1;
>                 break;
>            end;
>            if i=z+1 then exit;
>            y1:=y1 div p;
>      until y1=0;
>      out:=true;
> end;
> begin
>      readln(x,y);z:=0;out:=false;
>      for i:=2 to x do
>          if x mod i=y mod i then
>          begin
>               check(i);
>               if out then break;
>          end;
>      if out then writeln(i)
>             else writeln('No solution');
>      readln;
> end.

>