#include<bits/stdc++.h>
using namespace std;
#define ll long long
char ans[50];
ll n,m,idx,g; 
int main(){
    freopen("wheel.in","r",stdin);
    freopen("wheel.out","w",stdout);
    while(cin>>n>>m){
        memset(ans,0,sizeof(ans));
        idx=0,g=0;
        for(int i=1;i<=m;i++){
            ll a;
            char b;
            cin>>a>>b;
            idx=(idx+a)%n;
//            cout<<idx<<endl;
            if(ans[idx]&&ans[idx]!=b){
                g=1;
            }else{
                ans[idx]=b;
            }
        }
        if(g){
            cout<<"!\n";
            continue;
        }
        for(int i=idx;i>=0;i--){
            if(ans[i])cout<<ans[i];
            else cout<<"?";
        }
        for(int i=n-1;i>idx;i--){
            if(ans[i])cout<<ans[i];
            else cout<<"?";
        }
        cout<<endl;
    }
    return 0;
}