using System;
class Program {
static void Main() {
string str = Hello World! Hello!;
Console.WriteLine(Occurrence:+Check.CheckOccurrences(str, Hello));
}
}
public static class Check {
public static int CheckOccurrences(string str1, string pattern) {
int count = 0;
int a = 0;
while ((a = str1.IndexOf(pattern, a)) != -1) {
a += pattern.Length;
count++;
}
return count;
}
}