Language: C++

#include<bits/stdc++.h>
using namespace std;

#define ll long long int
#define pi 3.141592653589793238
#define fast ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define mod 1000000007

ll ceil1(ll n,ll m){if(n%m==0){return n/m;}return n/m +1;}

ll factor(ll n){
    vll ans;
	if(n==2)ans.pb(2);
	else
    {for(ll i=2;i*i<=n;i++){if(n%i==0 && n%i!=i){ans.pb(i);if(n/i!=i)ans.pb(n/i);}}ans.pb(n);}
    return ans.sz+1;
}
ll fact(ll n){ll res = 1;for (ll i = 2; i <= n; i++)res = res * i; 
    return res; } 
  
ll nCr(ll n, ll r){ return fact(n) / (fact(r) * fact(n - r)); } 
  
void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
{
    par[k]=p;
    dis[k]=dis[p]+1;
    for(ll i=0;i<v[k].sz;i++){
        if(v[k][i]!=p){
            dfs(v,v[k][i],par,dis,k);
        }
    }
}
bool sortbysec(const pair<string,int> &a,const pair<string,int> &b){return (a.second<b.second);} 

ll pow2(ll n,ll k){ll ans=1;
    while(k>0){
        if(k%2==1)ans=ans*n;n=n*n;k/=2;
    }return ans;}
bool prime(int n){
    int i,j;
    for(i=2;i<=sqrt(n);i++){
        if(n%i==0){
            return false;
        }
    }
    return true;
}

void solve()
{
	ll a,b;
	cin>>a>>b;
	if((a+b)%3==0)
		cout<<"Possible";
	else
		cout<<"Impossible";
}            
int main()
{
	fast;
    ll q;
    q=1;
    // cin>>q;
    while(q--)
    {
        solve();
    }
    return 0;
}


Compiler output:
a.cc: In function 'long long int factor(long long int)':
a.cc:12:5: error: 'vll' was not declared in this scope; did you mean 'll'?
   12 |     vll ans;
      |     ^~~
      |     ll
a.cc:13:17: error: 'ans' was not declared in this scope; did you mean 'abs'?
   13 |         if(n==2)ans.pb(2);
      |                 ^~~
      |                 abs
a.cc:15:50: error: 'ans' was not declared in this scope; did you mean 'abs'?
   15 |     {for(ll i=2;i*i<=n;i++){if(n%i==0 && n%i!=i){ans.pb(i);if(n/i!=i)ans.pb(n/i);}}ans.pb(n);}
      |                                                  ^~~
      |                                                  abs
a.cc:15:84: error: 'ans' was not declared in this scope; did you mean 'abs'?
   15 |     {for(ll i=2;i*i<=n;i++){if(n%i==0 && n%i!=i){ans.pb(i);if(n/i!=i)ans.pb(n/i);}}ans.pb(n);}
      |                                                                                    ^~~
      |                                                                                    abs
a.cc:16:12: error: 'ans' was not declared in this scope; did you mean 'abs'?
   16 |     return ans.sz+1;
      |            ^~~
      |            abs
a.cc: At global scope:
a.cc:23:6: error: variable or field 'dfs' declared void
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |      ^~~
a.cc:23:10: error: 'vllv' was not declared in this scope; did you mean 'll'?
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |          ^~~~
      |          ll
a.cc:23:16: error: 'v' was not declared in this scope
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |                ^
a.cc:4:12: error: expected primary-expression before 'long'
    4 | #define ll long long int
      |            ^~~~
a.cc:23:18: note: in expansion of macro 'll'
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |                  ^~
a.cc:23:23: error: 'vll' was not declared in this scope; did you mean 'll'?
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |                       ^~~
      |                       ll
a.cc:23:28: error: 'par' was not declared in this scope; did you mean '__pstl::execution::v1::par'?
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |                            ^~~
      |                            __pstl::execution::v1::par
In file included from /usr/include/c++/14/pstl/glue_algorithm_defs.h:15,
                 from /usr/include/c++/14/algorithm:86,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/pstl/execution_defs.h:43:45: note: '__pstl::execution::v1::par' declared here
   43 | _GLIBCXX17_INLINE constexpr parallel_policy par{};
      |                                             ^~~
a.cc:23:32: error: 'vll' was not declared in this scope; did you mean 'll'?
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |                                ^~~
      |                                ll
a.cc:23:37: error: 'dis' was not declared in this scope; did you mean 'div'?
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |                                     ^~~
      |                                     div
a.cc:4:12: error: expected primary-expression before 'long'
    4 | #define ll long long int
      |            ^~~~
a.cc:23:41: note: in expansion of macro 'll'
   23 | void dfs(vllv &v,ll k,vll &par,vll &dis,ll p)
      |                                         ^~