import sys
header_line = sys.stdin.readline()
header_line = header_line.split(" ")
R = int(header_line[0])
C = int(header_line[1])
D = int(header_line[2])
K = int(header_line[3])
G = []
for i in range(R):
G.append(sys.stdin.readline())
P = []
for i in range(R + 1):
P_row = []
for j in range(C + 1):
P_row.append(0)
P.append(P_row)
for i in range(R):
for j in range(C):
if G[i][j] == 'S':
li = max(0, i - D)
hi = min(R - 1, i + D)
lj = max(0, j - D)
hj = min(C - 1, j + D)
P[li][lj] += 1
P[li][hj + 1] -= 1
P[hi + 1][lj] -= 1
P[hi + 1][hj + 1] += 1
for i in range(1, R):
for j in range(C):
P[i][j] += P[i - 1][j]
for i in range(R):
for j in range(1, C):
P[i][j] += P[i][j - 1]
ans = 0
for i in range(R):
for j in range(C):
if G[i][j] == 'M' and P[i][j] >= K:
ans += 1
print(ans)
