#include<bits/stdc++.h>
using namespace std;
int main(){
	//freopen("char.in","r",stdin);
	//freopen("char.out","w",stdout);
	char a[100000],b;
	int c,n,s=1,max1=0;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		c=a[i];
		if(c-int(a[i-1])==1){
			s++; 
		}
		else{
            if(s>max1){
			max1=s;
		}
			s=1;
		}
	}
	cout<<max1;
	return 0;
}
```


```