Rescue SOS Signal Analysis

The rescue center receives numerous SOS signals each day. After receiving a signal, the center analyzes it by counting the number of times the substring sos appears in the signal. Note that occurrences of sos can overlap, e.g. sosos contains 2 occurrences because the substrings starting at indices 0 and 2 both form sos (i.e., it counts as $2$ occurrences).

Your task is to help the rescue center determine the urgency of a given rescue signal by computing the number of times the substring sos appears. A larger count indicates a more urgent situation.

inputFormat

The input consists of a single line containing a string made up of lowercase English letters.

Constraints: The string length will be at least 1.

outputFormat

Output a single integer that represents the number of times the substring sos appears in the input string. Overlapping occurrences should be counted.

sample

sos

1