View Compilation Error

0_0_13763274_8861.cpp: In function 'int main()':
0_0_13763274_8861.cpp:8:8: error: 'cin' was not declared in this scope
  while(cin>>m>>n)
        ^
0_0_13763274_8861.cpp:25:3: error: 'cout' was not declared in this scope
   cout<<step<<endl;
   ^
0_0_13763274_8861.cpp:25:15: error: 'endl' was not declared in this scope
   cout<<step<<endl;
               ^