graph = [[0 for _ in range(26**2)] for _ in range(26**2)]

edges = []

with open("day23") as f:
    for l in f:
        (a,b) = l.strip().split('-')
        x = (ord(a[0])-ord('a'))*26 + (ord(a[1])-ord('a'))
        y = (ord(b[0])-ord('a'))*26 + (ord(b[1])-ord('a'))

        graph[x][y] = 1
        graph[y][x] = 1

        edges.append((x,y))

components = []
for edge in edges:
    a = edge[0]
    b = edge[1]
    for c, e in enumerate(graph[b]):
        if e == 1 and graph[c][a] == 1:
            components.append((a,b,c))

t_components = set()
for component in components:
    for c in component:
        if c >= 494 and c<520:
            t_components.add(tuple(sorted(component)))

print(len(t_components))


def find_component(start):
    component = [start[0],start[1]]

    changed = True
    while changed:
        changed = False
        a = component[-1]

        candidates = []
        for b, e in enumerate(graph[a]):
            if e == 1: candidates.append(b)

        for candidate in candidates:
            for comp in component:
                if graph[comp][candidate] != 1: break
            else:
                component.append(candidate)
                changed = True
    return component

components = []
for edge in edges:
    components.append(find_component(edge))

max_len = 0
max_idx = -1
for idx, c in enumerate(components):
    if len(c) > max_len:
        max_len = len(c)
        max_idx = idx

max_component = components[max_idx]
max_component_alpha = []
for mc in max_component:
    a = chr(ord('a')+(mc//26))
    b = chr(ord('a')+(mc%26))
    max_component_alpha.append(a+b)
print(','.join(sorted(max_component_alpha)))