View Compilation Error

0_0_19571396_26509.cpp: In function 'int main()':
0_0_19571396_26509.cpp:3:35: error: 'scanf' was not declared in this scope
     while(~scanf("%d %d", &a1, &a2)) {
                                   ^
0_0_19571396_26509.cpp:7:29: error: 'printf' was not declared in this scope
             printf("Sorry\n");
                             ^
0_0_19571396_26509.cpp:9:29: error: 'printf' was not declared in this scope
             printf("Sorry\n");
                             ^
0_0_19571396_26509.cpp:11:29: error: 'printf' was not declared in this scope
             printf("Sorry\n");
                             ^
0_0_19571396_26509.cpp:13:26: error: 'printf' was not declared in this scope
             printf("OK\n");
                          ^