int main(){
int a[100]={},i,n,s=0;
char x[31];
scanf("%d",&n);
while(~scanf("%s",x))a[i++%n]+=!strcmp(x,"nyanpass");
for(i=0;i<100;)s=a[i++]+1-n?s:s?-1:i;
printf("%d",s?s:-1);
return 0;
}