/in/foo.cc:1:11: error: 'N' was not declared in this scope
 int prime[N*5000];
           ^
/in/foo.cc:2:13: error: 'N' was not declared in this scope
 int isPrime[N*5000];
             ^
/in/foo.cc:3:9: error: 'N' was not declared in this scope
 int phi[N*5000];
         ^
/in/foo.cc: In function 'void init()':
/in/foo.cc:7:5: error: 'prime' was not declared in this scope
     prime[0]=0;
     ^~~~~
/in/foo.cc:8:10: error: 'phi' was not declared in this scope
     fill(phi,phi+5000001,1);
          ^~~
/in/foo.cc:8:5: error: 'fill' was not declared in this scope
     fill(phi,phi+5000001,1);
     ^~~~
/in/foo.cc:10:12: error: 'isPrime' was not declared in this scope
     memset(isPrime,0,sizeof(isPrime));
            ^~~~~~~
/in/foo.cc:10:5: error: 'memset' was not declared in this scope
     memset(isPrime,0,sizeof(isPrime));
     ^~~~~~
/in/foo.cc:17:17: error: 'LL' was not declared in this scope
             if((LL)i*(LL)prime[j]>5000000) break;
                 ^~
/in/foo.cc:17:20: error: expected ')' before 'i'
             if((LL)i*(LL)prime[j]>5000000) break;
                    ^