题解

#include<iostream>
#include<algorithm>
using namespace std;

int a[110];

int main(){
    int n,k;
    cin>>n>>k;
    for (int i=0;i<n;i++) cin>>a[i];
    sort(a,a+n);
    for (int i=0;;i++){
        if (!binary_search(a,a+n,i*k)){
            cout<<i*k;
            break;
        }
    }
    return 0;
}