from collections import deque


def bfs(g, st):
    global used, n, m
    queue = deque([st])
    used[st[0]][st[1]] = True
    while len(queue) != 0:
        v = queue.popleft()
        p = []
        if v[0] < n - 1 and g[v[0] + 1][v[1]] != g[v[0]][v[1]]:
            p.append((v[0] + 1, v[1]))
        if v[0] > 0 and g[v[0] - 1][v[1]] != g[v[0]][v[1]]:
            p.append((v[0] - 1, v[1]))
        if v[1] < m - 1 and g[v[0]][v[1] + 1] != g[v[0]][v[1]]:
            p.append((v[0], v[1] + 1))
        if v[1] > 0 and g[v[0]][v[1] - 1] != g[v[0]][v[1]]:
            p.append((v[0], v[1] - 1))
        for u in p:
            if not used[u[0]][u[1]]:
                queue.append(u)
                used[u[0]][u[1]] = True
    return

fin = open("chessboard.in", "r")
fout = open("chessboard.out", "w")
n, m = map(int, fin.readline().split())
lst = []
used = []
for i in range(n):
    s = fin.readline().rstrip()
    lst.append([])
    used.append([False] * m)
    for j in s:
        lst[-1].append(j)
ans = 0

for i in range(n):
    for j in range(m):
        if not used[i][j]:
            bfs(lst, (i, j))
            ans += 1

print(ans, file=fout)