Convert from light year to inch [international, U.S.]

Unit Definition (light year)
The distance that light, moving at a constant speed of 300,000 km/s, travels in one year. One light year is about 10 trillion kilometers.

Unit Definition (inch [international, U.S.])
The inch is a traditional measurement of distance equal to 1/12 of a foot, or exactly 2.54 centimeters. The Old English word "ynce" is derived from the Latin uncia, meaning a 1/12 part. It follows that "inch" and "ounce" actually have the same origin. The inch was originally defined in England in two ways: as the length of three barleycorns laid end to end, or as the width of a man's thumb at the base of the nail. The barleycorn definition is peculiarly English, but the thumb-width definition is generic. In many european languages the word for inch actually also means thumb: examples include the Dutch duim, Swedish tum, French pouce, and Spanish pulgada. In the history of English units the inch seems to come before the foot, as after the Norman conquest of 1066, the foot was defined as 12 inches, rather than the inch being defined as 1/12 foot.