#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>
#include "math.h"
#include <stack>

#define MAXN 300

using namespace std;

int input[MAXN*2];
stack<int> m_stack;

int main(){
    int N(0),K(0);
    cin>>N>>K;
    for(int i=0;i<N+K;i++){
        cin>>input[i];
    }
    int count(0);
    int iter(0);
    int temp = input[iter];
    count++;
    while(count<N){
        if(temp==input[count]){
            input[iter]++;
            input[count]=-1;
            if(iter>0){
                iter--;}
            while(iter>0&&input[iter]==-1)
                iter--;
            
            temp = input[iter];
            count--;
            while(input[count]==-1)
                count--;
            if(count==iter){
                count++;
                while(input[count]==-1){
                count++;
                }
            }
            N++;
        }
        else{
        iter++;
        count++;
        while(input[iter]==-1)
            iter++;
        while(input[count]==-1)
            count++;
        temp = input[iter];
    
        }

    }
    int max=0;
    for(int i=0;i<N;i++){
    if(input[i]>max)
        max = input[i];
    
    }
    cout<<"max is "<<max<<endl;
    system("pause");


return 0;
}