n = 325396
b = [2, 0] * (n + 1)
b[2] = 0
d = 0
y = len(b)
#0 - простое

def f():
    for i in range(3, round(325396.0 ** 0.5) + 1, 2):
        if b[i] == 0:
            for j in range(2*i, y, i):
                b[j] = i

#236228; 305283

f()
for i in range(278932, 325396):
    k = 0
    a = i
    sch = 0
    if b[a] != 0:
        c = b[a] % 10
        a = a // b[a]
        if b[a] != 0 and c == b[a] % 10:
            a = a // b[a]
            if b[a] == 0 and c == a % 10:
                d = d + 1

#    while b[a] != 0 and sch != 1:
#        a = a // b[a]
#        sch = sch + 1
#        if c != b[a] % 10:
#            k = 1
#    if b[a] == 0 and sch == 1 and c == b[a] % 10 and k == 0:
#        d = d + 1

print(d)