View Compilation Error

0_0_25600068_9969.cpp: In function 'int main()':
0_0_25600068_9969.cpp:84:26: error: invalid conversion from 'int*' to 'size_t {aka long long unsigned int}' [-fpermissive]
     memset(first,-1,first);
                          ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/cstring:42:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/x86_64-w64-mingw32/bits/stdc++.h:48,
                 from 0_0_25600068_9969.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/string.h:43:18: note: initializing argument 3 of 'void* memset(void*, int, size_t)'
   void * __cdecl memset(void *_Dst,int _Val,size_t _Size);
                  ^