View Compilation Error

0_0_18994139_8123.cpp: In function 'int main()':
0_0_18994139_8123.cpp:94:29: error: 'n' was not declared in this scope
         for (int i = 0; i < n; ++i)
                             ^
0_0_18994139_8123.cpp:96:5: error: 'cin' was not declared in this scope
     cin >> w[i][j];        printf("%d\n",KM());
     ^
0_0_18994139_8123.cpp:96:5: note: suggested alternative:
In file included from 0_0_18994139_8123.cpp:3:0:
GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^