By Yannis Behrakis IDOMENI, Greece (Reuters) - After a brief respite aboard a Greek passenger ship, Syrian refugee Mohamed has found himself stranded on a filthy, chaotic strip at the Macedonian border, his way to the relative security of northern Europe blocked by razor wire and riot police. The 20-year-old geology student, like thousands of others stuck at the Greek frontier village of Idomeni, has made an arduous and often dangerous journey to escape the horrors of the Syrian civil war. What he has found at Idomeni has brought him close to despair and now he simply wants to go anywhere in Europe that is safe.