#include <iostream>
using namespace std;
int main() {
int a;
int cnt=0;
cin >> a;
while (a > 0){
if ((a%10)%2==1){
cnt++;
}
a/=10;
}
cout << cnt;
return 0;
}
I2luY2x1ZGUgPGlvc3RyZWFtPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwoKaW50IG1haW4oKSB7CglpbnQgYTsKCWludCBjbnQ9MDsKCWNpbiA+PiBhOwoJd2hpbGUgKGEgPiAwKXsKCQlpZiAoKGElMTApJTI9PTEpewoJCWNudCsrOwkKCQl9CgkJYS89MTA7Cgl9Cgljb3V0IDw8IGNudDsKCXJldHVybiAwOwp9