    #include <stdio.h>
    #include <limits.h> 
    #include <stdlib.h>
     
    int main(void) {
        int a[100],e[100];int i,o,j;
    	for(i=0;i<100;i++){
    	    a[i]=i+1;
    	}
    	int b,c;
    	scanf ("%d%d",&b,&c);
    	if(c==0){printf("%d",b);return 0;}
    	int d[c];
        for(i=0;i<c;i++){
            scanf("%d",&d[i]);
        }
        for(i=0;i<100;i++){
            for(o=0;o<c;o++){
            if (a[i]==d[o]){a[i]=0;}
        }}
        for(i=0;i<100;i++){
            if(a[i]<=b){e[i]=b-a[i];}
            else{e[i]=a[i]-b;}
            }
        for(i=0;i<100;i++){
            for(j=i+1;j<100;j++){
            if(e[i]>e[j]){
                o=e[i];
                e[i]=e[j];
                e[j]=o;
        }}}
        i=e[0]+b;o=b-e[0]-1;
        if(a[o]==0){printf("%d",i);}
        else{printf("%d",o+1);}
        return 0;
    }