#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

#define HASH_BITS 20
long hash[1<<HASH_BITS];

char rbuf[200004];
main(){
	int n=read(0,rbuf+1,(sizeof rbuf)-1);
	rbuf[n]=0;
	rbuf[0]=97;
	char*rp=rbuf;
	long x[100];
	x[97]=0;
	x[98]=1;
	x[99]=1e9+7;
	long s=0;
	int z=0;
	for(int c;c=*rp++,c;){
		x[c]=s-x[c]*2;
		s=x[97]+x[98]+x[99];
		int h=s&(1<<HASH_BITS)-1;
		while(1){
			if(hash[h]==0){
				hash[h]=s;
				++z;
				break;
			}
			if(hash[h]==s){
				break;
			}
			h=h+1&(1<<HASH_BITS)-1;
		}
	}
	{
		long n=0,d=0;
		while(++n,d=d<<8|0x30|z%10,z/=10);
		write(1,&d,n);
	}
	_exit(0);
}