rt

#include<bits/stdc++.h>
using namespace std;
char z[33];
bool f[33];
int main()
{
	int n,k,x=0;
	cin>>n>>k;
	while(k--)
	{
		int s;
		char c;
		cin>>s>>c;
		x=(x+s)%n;
		if(z[x]&&z[x]!=c||f[c]&&z[x]!=c)
		{
			cout<<'!';
			return 0;
		}
		z[x]=c;
		f[c]=1;
	}
	for(int i=x;i>=0;i--)
	{
		if(z[i]) cout<<z[i];
		else cout<<'?';
	}
	for(int i=n-1;i>x;i--)
	{
		if(z[i]) cout<<z[i];
		else cout<<'?';
	}
	return 0;
}