pastas

def resp():
    completos = n/p
    resto = n%p
    for i in range(1, p+1):
        if resto:
            if lista[i] != (completos + 1):
                print "N"
                return 0;
            resto -= 1
        else:
            if lista[i] != completos:
                print "N"
                return 0;
    print "S"

p, n = map(int, raw_input().split())

lista = [0 for i in range(p+1)]
for i in range(n):
    val = int(raw_input())
    lista[val] += 1

resp()