It is known that the three side lengths a, b, and c of a triangle are unequal positive integers, and the least common multiple of a, b, and c is 60, and the greatest common divisor of the shorter two sides is 4, then the perimeter of the triangle is the smallest What is the value.
已知三角形的三边长a，b，c是互不相等的正整数，且a，b，c的最小公倍数是60，较短两边的最大公约数是4，则此三角形的周长的最小值为多少．
<result>31</result>