<human>:  replace a pattern with single slash in.
<bot>:)', r'\1\2', string)

# Enter the string
string = "a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z"

# Calling the function
print((replace_slash(string)))

#Example Output
# ab/cd/ef/gh/ij/kl/mn/op/qr/st/uv/wx/yz

#Remember to inspect code for bugs.