#!/usr/bin/env python3
import numpy as np
from scipy.signal import convolve

lines = (x.strip() for x in open("input.txt"))

blacks = set()

for line in lines:
    x, y = 0, 0
    while len(line):
        if line[0] == "n":
            y += 1
            x += 1 if line[1] == "e" else 0
            line = line[2:]
        elif line[0] == "s":
            y -= 1
            x -= 1 if line[1] == "w" else 0
            line = line[2:]
        else:
            x += 1 if line[0] == "e" else -1
            line = line[1:]
    if (x, y) in blacks:
        blacks.discard((x, y))
    else:
        blacks.add((x, y))


x = np.array(list([x, y] for x, y in blacks)).T
lower = np.min(x, axis=1)
upper = np.max(x, axis=1)
grid = np.zeros((upper[0]-lower[0]+1, upper[1]-lower[1]+1))
x -= np.array([lower]).T
grid[x[0], x[1]] = 1
kernel = np.array([
    [1, 1, 0],
    [1, 0, 1],
    [0, 1, 1]
])

for _ in range(100):
    grid = np.pad(grid, pad_width=1)
    neighbors = convolve(grid, kernel, mode='same', method="direct")
    set_inactive = np.logical_and(grid == 1, np.logical_or(neighbors == 0, neighbors > 2))
    set_active = np.logical_and(grid == 0, neighbors == 2)
    grid[set_inactive] = 0
    grid[set_active] = 1
    a = tuple(slice(np.min(idxs), np.max(idxs)+1) for idxs in np.where(grid == 1))
    grid = grid[a]

print(np.sum(grid))