The subroutine INDEX_OF finds the first position of a character in a string using 0-based indexing.

For example, INDEX_OF('Network', 'o') would return 4.

The variable y is assigned a value using the following statement:

y ← INDEX_OF(destination, 'o')

Figure 1

continent ← 'South America'
country ← 'Argentina'
capital ← 'Buenos Aires'
destination ← 'Patagonia region'

Using Figure 1, what value is assigned to y?