#include<bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define fir first
#define sec second

#define modPrepare() \
void Add(int &x,int y){(x+=y)>=Mod?x-=Mod:x;}\
void Del(int &x,int y){(x-=y)<0?x+=Mod:x;}\
int Pow(int a,int b){\
	int res=1;\
	while(b){\
		if(b&1) res=1ll*res*a%Mod;\
		a=1ll*a*a%Mod,b>>=1;\
	}\
	return res;\
}

#define facPrepare(_) \
const int len=_;\
int Fac[len+10],Iac[len+10]; \
void facInit(){\
	Fac[0]=Iac[0]=1;\
	for(int i=1;i<=len;++i) Fac[i]=1ll*Fac[i-1]*i%Mod;\
	Iac[len]=Pow(Fac[len],Mod-2);\
	for(int i=len-1;i;--i) Iac[i]=1ll*Iac[i+1]*(i+1)%Mod;\
}\
int Binom(int x,int y){return x<y?0:1ll*Fac[x]*Iac[y]%Mod*Iac[x-y]%Mod;}

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef pair<int,int> pii;

void read(int& x){
    static char c;int f=0;
    while(!isdigit(c=getchar()))
        if(c=='-') f=1;
    x=c^48;
    while(isdigit(c=getchar())) x=(x*10)+(c^48);
    if(f) x=-x;
}
void read(ll& x){
    static char c;int f=0;
    while(!isdigit(c=getchar()))
    	if(c=='-') f=1;
    x=c^48;
    while(isdigit(c=getchar())) x=(x*10)+(c^48);
    if(f) x=-x;
}
void read(uint& x){
    static char c;
    while(!isdigit(c=getchar()));x=c^48;
    while(isdigit(c=getchar())) x=(x*10)+(c^48);
}
void read(ull& x){
    static char c;
    while(!isdigit(c=getchar()));x=c^48;
    while(isdigit(c=getchar())) x=(x*10)+(c^48);
}
void chkmax(int& x,int y){if(y>x)x=y;}
void chkmin(int& x,int y){if(y<x)x=y;}
void chkmax(ll& x,ll y){if(y>x)x=y;}
void chkmin(ll& x,ll y){if(y<x)x=y;}
void chkmax(uint& x,uint y){if(y>x)x=y;}
void chkmin(uint& x,uint y){if(y<x)x=y;}
void chkmax(ull& x,ull y){if(y>x)x=y;}
void chkmin(ull& x,ull y){if(y<x)x=y;}

int n;
vector<string> str;

void Work(){
	read(n),str.resize(n);
	for(int i=0;i<n;++i) cin>>str[i];
	vector<char> Buc(26);
	for(int i=0;i<n;++i) ++Buc[str[i][0]-'A'];
	for(int i=0;i<n;++i){
		int flag=1,len=str[i].length();
		for(int j=0;j<len;++j)
			if(!Buc[str[i][j]-'A']) flag=0;
		if(flag) return puts("Y"),void();
	}
	puts("N");
}

int main(){Work();}