BEGIN {
	FS = OFS = "	";
}

($4 == "North America") {
	$4 = "NA";
}

($4 == "South America") {
	$4 = "SA";
}

{
	print;
}

USSR	8649	275	Asia
Canada	3852	25	NA
China	3705	1032	Asia
USA	3615	237	NA
Brazil	3286	134	SA
India	1267	746	Asia
Mexico	762	78	NA
France	211	55	Europe
Japan	144	120	Asia
Germany	96	61	Europe
England	94	56	Europe