View Compilation Error

0_0_22032695_17950.cpp: In function 'int main()':
0_0_22032695_17950.cpp:83:27: error: 'scanf' was not declared in this scope
  while(scanf("%d %d",&n,&m)!=EOF)
                           ^
0_0_22032695_17950.cpp:83:30: error: 'EOF' was not declared in this scope
  while(scanf("%d %d",&n,&m)!=EOF)
                              ^
0_0_22032695_17950.cpp:86:11: error: 'getchar' was not declared in this scope
   getchar();
           ^
0_0_22032695_17950.cpp:93:10: error: 'gets' was not declared in this scope
    gets(a);
          ^
0_0_22032695_17950.cpp:103:32: error: 'printf' was not declared in this scope
   if(ans!=-1) printf("%d\n",ans);
                                ^
0_0_22032695_17950.cpp:104:69: error: 'printf' was not declared in this scope
   else printf("Poor ANGEL has to stay in the prison all his life.\n");
                                                                     ^