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

char*mmap();
#define rd_skip() while(*rp++>=48)

#define wt_rev(v) {long _z=v;do*--wp=_z%10+48;while(_z/=10);}

#define rep(v,e) for(int v=0;v<e;++v)
#define chmax(v,a) (v=v>=a?v:a)

int mtx[26][26];
int kokomade[26];

main(){
	char*rp=mmap(0l,1l<<25,1,2,0,0ll);
	rd_skip();
	int c;

	while(*rp){
		char*p0=rp;
		int c0=*rp++;
		int c1=c0;
		int c;
		while(c=*rp++,c!=10){
			if(c<c1) goto skip;
			c1=c;
		}
		int len=rp-p0-1;
		c0-='a';
		c1-='a';
		if(c0!=c1){
			chmax(mtx[c0][c1],len);
		}else{
			mtx[c0][c1]+=len;
		}
		continue;

		skip:;
		while(*rp++!=10);
	}

	int best=0;
	rep(i,26){
		rep(j,i){
			chmax(kokomade[i],kokomade[j]+mtx[j][i]);
		}
		kokomade[i]+=mtx[i][i];
		chmax(best,kokomade[i]);
	}
	
	char wbuf[64],*wp=wbuf+sizeof wbuf;
	wt_rev(best);
	write(1,wp,wbuf+sizeof wbuf-wp);
	_exit(0);
}