/*
     Hell, 'til I reach Hell, I ain't scared
     Mama checkin' in my bedroom, I ain't there
                                                */
    #include<bits/stdc++.h>
    #include <ext/pb_ds/assoc_container.hpp>
    #include <ext/pb_ds/tree_policy.hpp>
    using namespace __gnu_pbds;
    using namespace std;

    #define Major  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #define TxtIO   freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
    #define read(a,n) for(int i = 0 ; i<n ; i++) cin>>a[i];
    #define write(a) for(auto x : a) cout<<x<<" ";
    #define int long long
    #define pb push_back
    #define all(a)  a.begin(),a.end()
    #define el "\n"

    typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

    const int inf=4e18;

    int dx[]={1,0,-1,0,1,1,-1,-1};
    int dy[]={0,1,0,-1,1,-1,1,-1};

    const int mod=1e9+7;
    const int MAX =1e6+7;

    //---------------------------Function----------------------------------//
    void TestCake(){
        int n;cin>>n;
        string s;cin>>s;
        int st=1;
        for(int i=0;i<s.size();i++){
            string here=to_string(st);
            string tmp="";

            for(int j=i;j<i+here.size();j++){
                tmp+=s[j];
            }
//               cout<<here<<" "<<tmp<<el;
            if(tmp==here){
                st++;
                i+=here.size()-1;
            }
            else{
                cout<<st<<el;return;
            }
        }

    }
    //------------------------------Main---------------------------//
    signed main(){
        Major
        int T = 1;
//        cin >> T;
        while(T--){
            TestCake();
        //       cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
        }
        return 0;
    }