43C - Lucky Tickets - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;
int a[105];
int main()
{
int n,c;
cin>>n;
for(int i=1;i<=n;i++){
cin>>c;
a[c%3]++;
}
cout<<a[0]/2+min(a[1],a[2]);
return 0;
}