fctrl easy

my solution works for test cases but it is marked wrong

using namespace std ;
int main()
{ int w ;
cin >> w ;
int sum ;
sum = w/5 + w/25 + w/ 125 + w/625 +w/3125 + w/15625 +w/78125 ;
cout << sum ;
return 0 ;

First: you’re supposed to accept a set of cases and report out on all of them; not just one value per run.

Algorithmically you seem to have the right idea, but the limit of 10^9 given for N means you haven’t taken it far enough. And in fact one of the given test cases shows that.