# http://c...content-available-to-author-only...e.com/a/51837/34718
f=lambda l:min(l)*all(x>0for x in l)+max(l)*all(x<0for x in l)
print f([2,3,4]), f([-4,-5,-9]), f([4,-3,8])
f=lambda l:eval("+m%s%s(l)*all(x%s0for x in l)"*2%tuple("ax<in>"))
print f([2,3,4]), f([-4,-5,-9]), f([4,-3,8])
IyBodHRwOi8vYy4uLmNvbnRlbnQtYXZhaWxhYmxlLXRvLWF1dGhvci1vbmx5Li4uZS5jb20vYS81MTgzNy8zNDcxOAoKZj1sYW1iZGEgbDptaW4obCkqYWxsKHg+MGZvciB4IGluIGwpK21heChsKSphbGwoeDwwZm9yIHggaW4gbCkgICAgCgpwcmludCBmKFsyLDMsNF0pLCBmKFstNCwtNSwtOV0pLCBmKFs0LC0zLDhdKQoKZj1sYW1iZGEgbDpldmFsKCIrbSVzJXMobCkqYWxsKHglczBmb3IgeCBpbiBsKSIqMiV0dXBsZSgiYXg8aW4+IikpCgpwcmludCBmKFsyLDMsNF0pLCBmKFstNCwtNSwtOV0pLCBmKFs0LC0zLDhdKQo=