#include <stdio.h>
signed main(){
   int x,n,p[105];
   scanf("%d %d",&x,&n);
   int i;
   for(i=0;i<n;i++);{
       scanf("%d",&p[i]);
   }
   int flag[105]={};
   int ans=0;
   for(i=0;i<n;i++){
       flag[p[i]]=1;
   }
   for(i=1;i<=101;i++){
       if(flag[i]==0){
           int abs1,abs2;
           abs1=x-ans;
           abs2=x-i;
           if(abs1<0){
               abs1=abs1*-1;
           }
           if(abs2<0){
               abs2=abs2*-1;
           }
           if(abs1>abs2){
               ans=i;
           }
       }
   }
   printf("%d\n",ans);
    return(0);
}