/in/foo.cc: In function 'int main()':
/in/foo.cc:46:44: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
   for(int i=2;i<=n;i++) scanf("%I64d",&a[i]);
                                            ^
/in/foo.cc:50:24: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
    printf("%I64d\n",ans);
                        ^
/in/foo.cc:56:21: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int' [-Wformat=]
    scanf("%I64d",res);
                     ^
/in/foo.cc:57:26: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
    printf("%I64d\n",res+i);
                          ^
/in/foo.cc:55:7: warning: 'res' may be used uninitialized in this function [-Wmaybe-uninitialized]
    ll res;
       ^~~