import std.algorithm, std.array, std.container, std.range, std.bitmanip;
import std.numeric, std.math, std.bigint, std.random, core.bitop;
import std.string, std.regex, std.conv, std.stdio, std.typecons;

void main()
{
  auto c1 = readln.chomp;
  auto c2 = readln.chomp;
  auto ci = c1 ~ c2;
  writeln(ci.splitter(regex(r"x+")).map!(a => a.length).reduce!(max));
}