answer.code: In function ‘int main()’:
answer.code:58:25: error: ‘printf’ was not declared in this scope
   58 |                         printf("0\n");
      |                         ^~~~~~
answer.code:3:1: note: ‘printf’ is defined in header ‘<cstdio>’; did you forget to ‘#include <cstdio>’?
    2 | #include<cmath>
  +++ |+#include <cstdio>
    3 | using namespace std;
answer.code:63:41: error: ‘printf’ was not declared in this scope
   63 |                                         printf("%d\n",2*(a[0]-1));
      |                                         ^~~~~~
answer.code:63:41: note: ‘printf’ is defined in header ‘<cstdio>’; did you forget to ‘#include <cstdio>’?
answer.code:65:41: error: ‘printf’ was not declared in this scope
   65 |                                         printf("0\n");
      |                                         ^~~~~~
answer.code:65:41: note: ‘printf’ is defined in header ‘<cstdio>’; did you forget to ‘#include <cstdio>’?
answer.code:70:41: error: ‘printf’ was not declared in this scope
   70 |                                         printf("6\n");
      |                                         ^~~~~~
answer.code:70:41: note: ‘printf’ is defined in header ‘<cstdio>’; did you forget to ‘#include <cstdio>’?
answer.code:74:41: error: ‘printf’ was not declared in this scope
   74 |                                         printf("0\n");
      |                                         ^~~~~~
answer.code:74:41: note: ‘printf’ is defined in header ‘<cstdio>’; did you forget to ‘#include <cstdio>’?