View Compilation Error

0_0_6643224_30086\Main.java:13: incompatible types
found   : int
required: boolean
            while (--n) s = s.multiply(BigInteger.valueof(n));
                   ^
0_0_6643224_30086\Main.java:13: cannot find symbol
symbol  : method valueof(int)
location: class java.math.BigInteger
            while (--n) s = s.multiply(BigInteger.valueof(n));
                                                 ^
2 errors