x=int(input())
def dj(x):
    r=True
    for a in range(2,int(x**0.5)+1):
        if x%a==0:
            r=False
            break
    return(r)
def op(i):
    s=str(i)[::-1]
    if s==str(i):
        return(True)
    else:
        return(False)
for i in range(10,x+1):
    if dj(i) and op(i):
        print(i)