Samsung Electronics Co., the world\'s second-largest maker of mobile phones, said Sunday its overseas sales of the Galaxy S2 smartphone topped the 3 million mark 55 days after its launch.  More than 3 million units of the Galaxy S2, which features a lighter and thinner body, and a faster processor than its predecessor, have been sold overseas since it was first launched in Britain in late April, according to the company. Samsung Electronics is making efforts to boost its overseas sales of the Android-based smartphone in a bid to take a bigger slice in the increasingly competitive smartphone markets. The company expects to sell 10 million units of the Galaxy S2 worldwide like its predecessor, the Galaxy S. The company last week held launching events in Mexico and Brazil in an effort to penetrate the fast growing South American markets.