Day 9 and it's just before iftar. Mustafa is helping out in the mosque kitchen and will be carrying out food to the members of the community who will be breaking their fast together..
He tucks his trousers into his socks so there’s no chance he will trip, and adjusts his fez one last time.
Uncle Idris hands Mustafa a plate of food and points across the hall.

"Careful now," he says. "Take this to Uncle Jerome."

The hall is already busy. People are seated at tables, chairs are pulled out, and narrow walkways weave between them. Mustafa must carry the plate without spilling a single grain of rice.

There is only one safe route.

The Floor Plan

The mosque hall is represented as a grid.
- Each character represents one square on the floor
- The layout you are given is the exact layout of the hall

Symbols

Symbol	Meaning
S	Mustafa’s starting position
G	Uncle Jerome (the goal)
.	Empty walkway (safe to walk on)
λ	Chair (safe to walk on)
#	Table (blocked — cannot be entered)

Movement Rules

Mustafa must obey all of the following rules:

Mustafa may move one square at a time

He may only move:

Up

Down

Left

Right

Diagonal movement is not allowed

Mustafa may not step onto tables (#)

Mustafa may step onto walkways (.) and chairs (λ)

Mustafa may not leave the bounds of the grid

Mustafa may not step on the same square more than once

The Task

Given the floor plan:

Determine whether Mustafa can reach Uncle Jerome

If he can:

Find the minimum number of steps required to do so

If he cannot:

Return IMPOSSIBLE

Expected Output

Return one value:

The minimum number of steps from S to G, or

IMPOSSIBLE if no valid path exists

Notes

The shortest route is not always the most obvious

Dead ends exist

Some routes appear promising but lead nowhere

Solving this by hand is impractical — careful reasoning or code is advised

Example

S . . #
# λ . #
# λ . G

A valid path exists:

S → . → . ↓
        λ ↓
        . → G

Total steps: 5