View Compilation Error

0_0_38447037_5869.cpp: In function 'int main()':
0_0_38447037_5869.cpp:10:3: error: expected ';' before 'll'
   ll x=log2(n-1);
   ^
0_0_38447037_5869.cpp:11:25: error: 'x' was not declared in this scope
   printf("%lld\n",(1LL<<x)-1);
                         ^