View Compilation Error

0_0_34127493_28149.cpp: In function 'bool check(it)':
0_0_34127493_28149.cpp:19:20: error: call of overloaded 'log2(it&)' is ambiguous
  it t = ceil(log2(n));
                    ^
0_0_34127493_28149.cpp:19:20: note: candidates are:
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/cmath:44:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/x86_64-w64-mingw32/bits/stdc++.h:41,
                 from 0_0_34127493_28149.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/math.h:638:25: note: double log2(double)
   extern double __cdecl log2 (double);
                         ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/x86_64-w64-mingw32/bits/stdc++.h:41:0,
                 from 0_0_34127493_28149.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/cmath:1468:3: note: constexpr long double std::log2(long double)
   log2(long double __x)
   ^
GCC4.9.2/x86_64-w64-mingw32/include/c++/cmath:1464:3: note: constexpr float std::log2(float)
   log2(float __x)
   ^