#include <stdio.h>
#include <stdlib.h>
#include <string.h>

long long gcd(long long a, long long b) {
    while (b != 0) {
        long long temp = b;
        b = a % b;
        a = temp;
    }
    return a;
}

long long lcm(long long a, long long b) {
    return a * b / gcd(a, b);
}

long long solution(int* coins, int coinsSize, int k) {
    long long left = coins[0], right = coins[0];
    
    for (int i = 0; i < coinsSize; i++) {
        if (coins[i] < left) left = coins[i];
        if (coins[i] > right) right = coins[i];
    }
    right *= k;
    
    while (left < right) {
        long long mid = left + (right - left) / 2;
        long long total = 0;
        
        for (int mask = 1; mask < (1 << coinsSize); mask++) {
            int subset[20];
            int subsetSize = 0;
            
            for (int i = 0; i < coinsSize; i++) {
                if (mask & (1 << i)) {
                    subset[subsetSize++] = coins[i];
                }
            }
            
            long long lcmVal = subset[0];
            for (int i = 1; i < subsetSize; i++) {
                lcmVal = lcm(lcmVal, subset[i]);
            }
            
            long long count = mid / lcmVal;
            
            if (subsetSize % 2 == 1) {
                total += count;
            } else {
                total -= count;
            }
        }
        
        if (total < k) {
            left = mid + 1;
        } else {
            right = mid;
        }
    }
    
    return left;
}

int main() {
    int coins[20];
    int coinsSize = 0;
    int k;
    
    char line[1000];
    fgets(line, sizeof(line), stdin);
    
    char* ptr = line + 1;
    char* token = strtok(ptr, ",]");
    while (token) {
        coins[coinsSize++] = atoi(token);
        token = strtok(NULL, ",]");
    }
    
    scanf("%d", &k);
    
    printf("%lld\n", solution(coins, coinsSize, k));
    return 0;
}