#include<bits/stdc++.h>
using namespace std;
int main(){
	string s,s1="a";
	char c='a';
	cin>>s;
	int sum=1,len=s.size();
	for(int i=0;i<len-1;i++){
		if(s[i]>=s[i+1]){
			cout<<0;
			return 0;
		}
	}
	for(int i=1;i<len;i++){
		sum+=26-i+1;
		c=c+1;
		s1+=c;
	}
	while(s!=s1){
		s1[len-1]++;
		for(int i=len-1;i>=0;i--){
			if(s1[i]=='z'+1){
				s1[i]='a'+i+1;
				s1[i-1]=s1[i-1]+1;				
			}
		}
		sum++;
//		cout<<s1<<" "<<sum<<"\n";
	}
	cout<<sum;
	return 0;
}