#include<bits/stdc++.h>
using namespace std;
int N,m,ch[105],t,flag=0;
char chi[105],s[105];
int main(){
    freopen("wheel.in","r",stdin);
    freopen("wheel.out","w",stdout);
    while(cin>>N>>m){
        for (int i=1;i<=m;i++){
            cin>>ch[i]>>chi[i];
        }
        for (int i=1;i<=100;i++) s[i]=0;
        t=1,flag=0;
        for (int i=m;i>=1;i--){
            if (s[t]&&s[t]!=chi[i]){
                cout<<"!"<<endl;
                flag=1;
                break;
            }
            s[t]=chi[i];
            t+=ch[i];
            if (t!=N) t=t%N;
        }
        if (flag==0){
            for (int i=1;i<=N;i++){
                if (s[i]) cout<<s[i];
                else cout<<"?";
            }
            cout<<endl;
        } 
        
    }
    return 0;
}