#include<stdio.h>
#include<math.h>
long int len(long int number){
	long int len=0;
	while ( number != 0){
		len+=1;
		number /=10;
		
	}
	return len;
}
int main(){
	long int n;
	scanf("%ld",&n);
	long int left = 0;
	long int right = len(n) -1;
	long int degree = 0;
	long int middle = len(n)/2;
	while ( middle>left){
		if((n/(int)pow(10,left))%10 == (n/(int)pow(10,right))%10 ){
			degree+=1;
			
		}
		left+=1;
		right-=1;
	}
	if(len(n)%2==0){
		printf("%ld",degree);
	}
	else{
		printf("%ld",degree+1);
	}

	return 0;
}