#include <stdio.h>
#include <bits/stdc++.h>
//%lld
typedef long long ll;
using namespace std;

int vetor[50005];
int v[50005];
int moedas[105];
int main(){
    int m, n;
    while(cin>>m){
        if(m!=0){
            memset(v, -1, sizeof(v));
            memset(vetor, 50005, sizeof(vetor));
            cin>>n;
            for(int i = 0;i<n;i++){
                cin>>moedas[i];
            }
            vetor[0] = 0;
            for(int i = 0;i<n;i++){
                for(int j = 0;j<=m;j++){
                    if(j>=moedas[i]){
                        vetor[j] = min(1+(vetor[j-moedas[i]]), vetor[j]);
                        v[j] = i;
                    }
                }

            }
            if(vetor[m]>50000)cout<<"Impossivel"<<endl;
            else cout<<vetor[m]<<endl;
        }else{
            break;
        }
    }
}