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

#define rd_init() char*rp=({char*mmap();mmap(0l,1l<<25,1,2,0,0ll);})
#define rd() ({int _v=0,_c;while(_c=*rp++-48,_c>=0)_v=_v*10+_c;_v;})
#define wt(v) ({unsigned _z=v;do*--wp=_z%10+48;while(_z/=10);})
#define wt1(v) ({char wbuf[64],*wp=wbuf+sizeof wbuf;wt(v);write(1,wp,wbuf+sizeof wbuf-wp);})
#define rep(v,e) for(typeof(e)v=0;v<e;++v)
#define chmin(v,a) (v=v<=a?v:a)

int a[3][128];

int main(){
	rd_init();
	int n=rd();
	rep(i,n){
		a[0][*rp++]+=1;
		a[1][*rp++]+=1;
		a[2][*rp++]+=1;
	}
	int z=a[0]['c'];
	chmin(z,a[1]['o']);
	chmin(z,a[2]['n']);
	if(z<n){
		int z1=a[1]['c'];
		chmin(z1,a[2]['o']);
		chmin(z1,a[0]['n']);
		int z2=a[2]['c'];
		chmin(z2,a[0]['o']);
		chmin(z2,a[1]['n']);
		z+=z1+z2;
		chmin(z,n-1);
	}
	wt1(z);
	_exit(0);
}