n = int(input())
m = int(input())
matrix = []
for i in range(n):
    row = list(map(float, input().split()))
    matrix.append(row)
product = 1.0
count = 0
for i in range(n):
    for j in range(m):
        if matrix[i][j] < 5:
            product *= matrix[i][j]
            count += 1
if count == 0:
    print("NOT")
else:
    print(f"{product:.3f}")