#include <bits/sdc++.h>  
using namespace std;  
bool canCookInTime(const vector<long long>& cookTimes, long long S, long long time) {  
    long long totalMeals = 0;  
    for (long long t : cookTimes) {  
        totalMeals += time / t;  
        if (totalMeals >= S) return true;  
    }  
    return false;  
}  
long long findMinimumTime(long long S, const vector<long long>& cookTimes) {  
    long long left = 1, right = *min_element(cookTimes.begin(), cookTimes.end()) * S;  
    while (left < right) {  
        long long mid = left + (right - left) / 2;  
        if (canCookInTime(cookTimes, S, mid)) right = mid;  
        else left = mid + 1;  
    }  
    return left;  
}  
int main() {   
    long long S, n;  
    input >> S >> n;  
    vector<long long> cookTimes(n);  
    for (long long i = 0; i < n; i++) input >> cookTimes[i];  
    output << findMinimumTime(S, cookTimes);  
    return 0;  
}