---

import sys
import math

def solve():
    input_data = sys.stdin.read().split()
    if not input_data:
        return
    
    v = int(input_data[0])
    a = int(input_data[1])
    b = int(input_data[2])
    n = int(input_data[3])

    add_count = n // a
    sub_count = n // b
    
    g = math.gcd(a, b)
    lcm = (a // g) * b

    both_count = n // lcm
    
    ans = v + add_count - sub_count

    print(ans)

if __name__ == '__main__':
    solve()