void main(){
  import std.stdio, std.string, std.conv, std.algorithm;
  import std.range;

  int m, n; rd(m, n);

  writefln("%.15f", m+n/3.0);

}

void rd(T...)(ref T x){
  import std.stdio, std.string, std.conv;
  auto l=readln.split;
  foreach(i, ref e; x){
    e=l[i].to!(typeof(e));
  }
}