Drazil is playing a math game with Varda.

Let's define <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/7020b94c48be2ee5b8eeca05f379c8911bb0e7c4.png" style="max-width: 100.0%;max-height: 100.0%;"/> for positive integer *x* as a product of factorials of its digits. For example, <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/6784d861d9a724d0aeddefcb00b7d0c3442ae586.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

First, they choose a decimal number *a* consisting of *n* digits that contains at least one digit larger than 1. This number may possibly start with leading zeroes. Then they should find maximum positive number *x* satisfying following two conditions:

1. *x* doesn't contain neither digit 0 nor digit 1.

2. <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/7020b94c48be2ee5b8eeca05f379c8911bb0e7c4.png" style="max-width: 100.0%;max-height: 100.0%;"/> = <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/aa57e017a6c74d06b0a54bc47e3f6990e5af38c1.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

Help friends find such number.
The first line contains an integer *n* (1 ≤ *n* ≤ 15) — the number of digits in *a*.

The second line contains *n* digits of *a*. There is at least one digit in *a* that is larger than 1. Number *a* may possibly contain leading zeroes.
n = input()
F_a = input()
mass_1 = []
mass_2 = []
mas = []
for i in F_a:
    mass_1.append(int(i))

for i in mass_1:
    if i == 2:
       mas = [2]
       if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
       else:
           mass_2.append(2)
    elif i == 3:
        mas = [3]
        if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
        else:
            mass_2.append(3)
    elif i == 4:
        mas = [3, 2, 2]
        if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
        else:
            mass_2.append(3)
            mass_2.append(2)
            mass_2.append(2)
    elif i == 5:
        mas = [5]
        if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
        else:
            mass_2.append(5)
    elif i == 6:
        mas = [5, 3]
        if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
        else:
            mass_2.append(5)
            mass_2.append(3)
    elif i == 7:
        mas = [7]
        if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
        else:
            mass_2.append(7)
    elif i == 8:
        mas = [7, 2, 2, 2]
        if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
        else:
            mass_2.append(7)
            mass_2.append(2)
            mass_2.append(2)
            mass_2.append(2)
    elif i == 9:
        mas = [7, 3, 3, 2]
        if len(mass_2) > 0:
            for j in mas:
                for y in range(len(mass_2)):
                    if j >= mass_2[y]:
                        mass_2.insert(y, j)
                        break
        else:
            mass_2.append(7)
            mass_2.append(3)
            mass_2.append(3)
            mass_2.append(2)
a = ''
for i in mass_2:
    a = a + str(i)
print(a)