#include <stdio.h>
int gcm(int a, int b, int c, int x);
int main()
{
    int a, b, c, x;
    scanf("%d %d %d %d", &a, &b, &c, &x);
    printf("%d\n", gcm(a, b, c, x));
    return 0;
}

int gcm(int a, int b, int c, int x)
{
    int yes = 1;
    for (int i = 1; i < x; i++)
    {
        if (i % a == 0 && i % b == 0 && i % c == 0)
        {
            return i;
            break;
        }
        else
        {
            yes = 0;
        }
    }
    if (yes == 0)
    {
        return -1;
    }
    
}