#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);
}
