n = int(input())
m = int(input())

matrix = []

for i in range(n):
    row = list(map(float, input().split()))
    matrix.append(row)

product = 1.0
found = False

for i in range(n):
    for j in range(m):
        if matrix[i][j] < 5:
            product *= matrix[i][j]
            found = True

if found:
    print(f"{product:.3f}")
else:
    print("NOT")